Mixtures of calcitonin drug-oligomer conjugates comprising polyalkylene glycol, uses thereof, and methods of making same

ABSTRACT

A mixture of conjugates in which each conjugate in the mixture comprises a calcitonin drug coupled to an oligomer that includes a polyalkylene glycol moiety is disclosed. The mixture may lower serum calcium levels in a subject by 10, 15 or even 20 percent or more. Moreover, the mixture may be more effective at surviving an in vitro model of intestinal digestion than non-conjugated calcitonin. Furthermore, the mixture may exhibit a higher bioavailability than non-conjugated calcitonin.

RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.09/873,777, filed Jun. 4, 2001, issued Mar. 30, 2004 as U.S. Pat. No.6,713,452, assigned to the assignee of the present invention, thedisclosure of which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates to drug-oligomer conjugates, and, moreparticularly, to calcitonin drug-oligomer conjugates.

BACKGROUND OF THE INVENTION

Calcitonin is a naturally occurring hormone with a short half-life thatis believed to act directly on osteoclasts (via receptors on the cellsurface for calcitonin). This action may directly inhibit osteoclasticbone resorption, which may lead to hypocalcemic and/or hypophosphatemicserum effects. Calcitonin may be useful in treating various bonedisorders including, but not limited to, osteoporosis and Paget'sdisease.

Osteoporosis is a bone disease in which bone tissue is normallymineralized, but the amount of bone is decreased and the structuralintegrity of trabecular bone is impaired. Cortical bone becomes moreporous and thinner. This makes the bone weaker and more likely tofracture. In the United States, about 21% of postmenopausal women haveosteoporosis (low bone density), and about 16% have had a fracture. Inwomen older than 80, about 40% have experienced a fracture of the hip,vertebra, arm, or pelvis. The population of older men and women has beenincreasing, and therefore the number of people with osteoporosis isincreasing.

Calcitonin given as a subcutaneous injection has shown significantimprovements in bone density; however, a high incidence of side effects,including pain at the injection site, flushing and nausea, have beenreported which may limit the use of the drug.

Paget's disease of bone is a metabolic bone disorder of unknown originwhich normally affects older people. The disease causes an increased andirregular formation of bone as the bone cells, which are responsible fordissolving the body's old bone and replacing it with new, become out ofcontrol. Over a period of time the deformed new bone becomes larger,weaker and has more blood vessels than normal bone. Unlike normal bone,the structure is irregular and consequently weaker, which makes it proneto fracture even after a minor injury.

In its mildest form the disease has no symptoms. In more severe casesthe pain can be intense. The relentless progression of the disease maycause bones to bow, the skull may increase in size and the spinal columnmay curve. As the bones enlarge they may cause pressure on nearby nerveswhich can result in muscle weakness. In the case of severe skullenlargement this pressure can result in deafness, disturbed vision,dizziness and tinnitus.

Calcitonin may be effective in treating disorders of increased skeletalremodeling, such as Paget's disease. In treating Paget's disease,chronic use of calcitonin may produce long-term reduction in symptoms;however, side effects of calcitonin administration may include nausea,hand swelling, urticaria, and intestinal cramping.

Various references have proposed conjugating polypeptides such ascalcitonin with polydispersed mixtures of polyethylene glycol orpolyethylene glycol-containing polymers. For example, U.S. Pat. No.5,359,030 to Ekwuribe proposes conjugating polypeptides such ascalcitonin with polydispersed mixtures of polyethylene glycol modifiedglycolipid polymers and polydispersed mixtures of polyethylene glycolmodified fatty acid polymers. The number average molecular weight ofpolymer resulting from each combination is preferred to be in the rangeof from about 500 to about 10,000 Daltons.

The polydispersity of the polymer mixtures and conjugates described inEkwuribe is likely a result of the use of polydispersed polyethyleneglycol in the polymer synthesis. PEG is typically produced bybase-catalyzed ring-opening polymerization of ethylene oxide. Thereaction is initiated by adding ethylene oxide to ethylene glycol, withpotassium hydroxide as catalyst. This process results in a polydispersedmixture of polyethylene glycol polymers having a number averagemolecular weight within a given range of molecular weights. For example,PEG products offered by Sigma-Aldrich of Milwaukee, Wis. are provided inpolydispersed mixtures such as PEG 400 (M_(n) 380–420); PEG 1,000 (M_(n)950–1,050); PEG 1,500 (M_(n) 1,400–1,600); and PEG 2,000 (M_(n)1,900–2,200).

It is desirable to provide non-polydispersed mixtures of calcitonindrug-oligomer conjugates where the oligomer comprises polyethyleneglycol.

SUMMARY OF THE INVENTION

It has unexpectedly been discovered that a mixture ofcalcitonin-oligomer conjugates comprising polyethylene glycol accordingto embodiments of the present invention may lower serum calcium levelsby 10, 15 or even 20 percent or more. Moreover, a mixture ofcalcitonin-oligomer conjugates comprising polyethylene glycol accordingto embodiments of the present invention may be more effective atsurviving an in vitro model of intestinal digestion than non-conjugatedcalcitonin. Furthermore, mixtures of calcitonin-oligomer conjugatescomprising polyethylene glycol according to embodiments of the presentinvention may exhibit a higher bioavailability than non-conjugatedcalcitonin.

According to embodiments of the present invention, a substantiallymonodispersed mixture of conjugates each comprising a calcitonin drugcoupled to an oligomer that comprises a polyethylene glycol moiety isprovided. The polyethylene glycol moiety preferably has at least 2, 3,or 4 polyethylene glycol subunits and, most preferably, has at least 7polyethylene glycol subunits. The oligomer preferably further comprisesa lipophilic moiety. The calcitonin drug is preferably salmoncalcitonin. Oligomers are preferably coupled at Lys¹¹ and Lys¹⁸ of thesalmon calcitonin. The conjugate is preferably amphiphilically balancedsuch that the conjugate is aqueously soluble and able to penetratebiological membranes.

According to other embodiments of the present invention, a substantiallymonodispersed mixture of conjugates is provided where each conjugateincludes salmon calcitonin covalently coupled at Lys¹⁸ of the salmoncalcitonin to a carboxylic acid moiety of a first oligomer thatcomprises octanoic acid covalently coupled at the end distal to thecarboxylic acid moiety to a methyl terminated polyethylene glycol moietyhaving at least 7 polyethylene glycol subunits, and covalently coupledat Lys¹⁸ of the salmon calcitonin to a carboxylic acid moiety of asecond oligomer that comprises octanoic acid covalently coupled at theend distal to the carboxylic acid moiety to a methyl terminatedpolyethylene glycol moiety having at least 7 polyethylene glycolsubunits.

According to still other embodiments of the present invention, asubstantially monodispersed mixture of conjugates is provided where eachconjugate comprises a calcitonin drug coupled to an oligomer comprisinga polyethylene glycol moiety, and the mixture is capable of loweringserum calcium levels in a subject by at least 5 percent.

According to yet other embodiments of the present invention, asubstantially monodispersed mixture of conjugates is provided where eachconjugate comprises a calcitonin drug coupled to an oligomer comprisinga polyethylene glycol moiety, and the mixture has an increasedresistance to degradation by chymotrypsin and/or trypsin when comparedto the resistance to degradation by chymotrypsin and/or trypsin of thecalcitonin drug which is not coupled to the oligomer.

According to other embodiments of the present invention, a substantiallymonodispersed mixture of conjugates is provided where each conjugatecomprises a calcitonin drug coupled to an oligomer comprising apolyethylene glycol moiety, and the mixture has a higher bioefficacythan the bioefficacy of the calcitonin drug which is not coupled to theoligomer.

According to still other embodiments of the present invention, a mixtureof conjugates is provided where each conjugate includes a calcitonindrug coupled to an oligomer that comprises a polyethylene glycol moiety,and the mixture has a molecular weight distribution with a standarddeviation of less than about 22 Daltons.

According to yet other embodiments of the present invention, a mixtureof conjugates is provided where each conjugate includes a calcitonindrug coupled to an oligomer that comprises a polyethylene glycol moiety,and the mixture has a dispersity coefficient (DC) greater than 10,000where

${DC} = \frac{( {\sum\limits_{i = 1}^{n}{N_{i}M_{i}}} )^{2}}{{\sum\limits_{i = 1}^{n}{N_{i}M_{i}^{2}{\sum\limits_{i = 1}^{n}N_{i}}}} - ( {\sum\limits_{i = 1}^{n}{N_{i}M_{i}}} )^{2}}$

wherein:

-   -   n is the number of different molecules in the sample;    -   N_(i) is the number of i^(th) molecules in the sample; and    -   M_(i) is the mass of the i^(th) molecule.

According to other embodiments of the present invention, a mixture ofconjugates is provided in which each conjugate includes a calcitonindrug coupled to an oligomer and has the same number of polyethyleneglycol subunits.

According to still other embodiments of the present invention, a mixtureof conjugates is provided in which each conjugate has the same molecularweight and has the formula:

wherein:

-   B is a bonding moiety;-   L is a linking group;-   G, G′ and G″ are individually selected spacer groups;-   R is a lipophilic group and R′ is a polyalkylene glycol group, or R′    is the lipophilic group and R is the polyalkylene oxide group;-   T is a terminating group;-   j, k, m and n are individually 0 or 1; and-   p is an integer from 1 to the number of nucleophilic residues on the    calcitonin drug.

Pharmaceutical compositions comprising conjugate mixtures of the presentinvention as well as methods of treating osteoporosis in a subject inneed of such treatment by administering an effective amount of suchpharmaceutical compositions are also provided. Additionally, methods ofsynthesizing such conjugate mixtures are provided.

Calcitonin-oligomer conjugate mixtures according to embodiments of thepresent invention may lower serum calcium levels by 20 percent or more.Moreover, such conjugates may provide decreased degradation byintestinal enzymes and/or provide increased bioavailability whencompared to non-conjugated calcitonin.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a generic scheme for synthesizing a mixture ofactivated polymers comprising a polyethylene glycol moiety and a fattyacid moiety according to embodiments of the present invention;

FIG. 2 illustrates a scheme for synthesizing a mixture of mPEG accordingto embodiments of the present invention;

FIG. 3 illustrates a scheme for synthesizing a mixture of activatedmPEG7-hexyl oligomers according to embodiments of the present invention;

FIG. 4 illustrates a scheme for synthesizing a mixture of activatedmPEG7-octyl oligomers according to embodiments of the present invention;

FIG. 5 illustrates a scheme for synthesizing a mixture of activatedmPEG-decyl oligomers according to embodiments of the present invention;

FIG. 6 illustrates a scheme for synthesizing a mixture of activatedstearate-PEG6 oligomers according to embodiments of the presentinvention;

FIG. 7 illustrates a scheme for synthesizing a mixture of activatedstearate-PEG8 oligomers according to embodiments of the presentinvention;

FIG. 8 illustrates a scheme for synthesizing a mixture of activated PEG3oligomers according to embodiments of the present invention;

FIG. 9 illustrates a scheme for synthesizing a mixture of activatedpalmitate-PEG3 oligomers according to embodiments of the presentinvention;

FIG. 10 illustrates a scheme for synthesizing a mixture of activatedPEG6 oligomers according to embodiments of the present invention;

FIG. 11 illustrates a scheme for synthesizing various propylene glycolmonomers according to embodiments of the present invention;

FIG. 12 illustrates a scheme for synthesizing various propylene glycolpolymers according to embodiments of the present invention;

FIG. 13 illustrates a scheme for synthesizing various propylene glycolpolymers according to embodiments of the present invention;

FIG. 14 illustrates a comparison of the average AUCs for variousmixtures of calcitonin-oligomer conjugates according to embodiments ofthe present invention with non-conjugated calcitonin, which is providedfor comparison purposes only and does not form part of the invention;

FIG. 15 illustrates a dose-response curve for a mixture ofmPEG7-octyl-calcitonin diconjugates according to embodiments of thepresent invention compared with a dose-response curve for calcitonin,which is provided for comparison purposes and is not a part of thepresent invention;

FIG. 16 illustrates a dose-response curve after oral administration of amixture of mPEG7-octyl-calcitonin diconjugates according to embodimentsof the present invention;

FIG. 17 illustrates a dose-response curve after subcutaneousadministration of a mixture of mPEG7-octyl-calcitonin diconjugatesaccording to embodiments of the present invention; and

FIG. 18 illustrates a dose-response curve after subcutaneousadministration of salmon calcitonin, which is provided for comparisonpurposes and is not part of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention will now be described with respect to preferredembodiments described herein. It should be appreciated however thatthese embodiments are for the purpose of illustrating the invention, andare not to be construed as limiting the scope of the invention asdefined by the claims.

As used herein, the term “non-polydispersed” is used to describe amixture of compounds having a dispersity that is in contrast to thepolydispersed mixtures described in U.S. Pat. No. 5,359,030 to Ekwuribe.

As used herein, the term “substantially monodispersed” is used todescribe a mixture of compounds wherein at least about 95 percent of thecompounds in the mixture have the same molecular weight.

As used herein, the term “monodispersed” is used to describe a mixtureof compounds wherein about 100 percent of the compounds in the mixturehave the same molecular weight.

As used herein, the term “substantially purely monodispersed” is used todescribe a mixture of compounds wherein at least about 95 percent of thecompounds in the mixture have the same molecular weight and have thesame molecular structure. Thus, a substantially purely monodispersedmixture is a substantially monodispersed mixture, but a substantiallymonodispersed mixture is not necessarily a substantially purelymonodispersed mixture.

As used herein, the term “purely monodispersed” is used to describe amixture of compounds wherein about 100 percent of the compounds in themixture have the same molecular weight and have the same molecularstructure. Thus, a purely monodispersed mixture is a monodispersedmixture, but a monodispersed mixture is not necessarily a purelymonodispersed mixture.

As used herein, the term “weight average molecular weight” is defined asthe sum of the products of the weight fraction for a given molecule inthe mixture times the mass of the molecule for each molecule in themixture. The “weight average molecular weight” is represented by thesymbol M_(w).

As used herein, the term “number average molecular weight” is defined asthe total weight of a mixture divided by the number of molecules in themixture and is represented by the symbol M_(n).

As used herein, the term “dispersity coefficient” (DC) is defined by theformula:

${DC} = \frac{( {\sum\limits_{i = 1}^{n}{N_{i}M_{i}}} )^{2}}{{\sum\limits_{i = 1}^{n}{N_{i}M_{i}^{2}{\sum\limits_{i = 1}^{n}N_{i}}}} - ( {\sum\limits_{i = 1}^{n}{N_{i}M_{i}}} )^{2}}$

-   -   wherein:        -   n is the number of different molecules in the sample;        -   N_(i) is the number of i^(th) molecules in the sample; and        -   M_(i) is the mass of the i^(th) molecule.

As used herein, the term “intra-subject variability” means thevariability in activity occurring within the same subject when thesubject is administered the same dose of a drug or pharmaceuticalcomposition at different times.

As used herein, the term “inter-subject variability” means thevariability in activity between two or more subjects when each subjectis administered the same dose of a given drug or pharmaceuticalformulation.

As used herein, the term “bioefficacy” means the ability of a drug ordrug conjugate to interact with one or more desired receptors in vivo.

As used herein, the term “calcitonin drug” means a drug possessing allor some of the biological activity of calcitonin.

As used herein, the term “calcitonin” means chicken calcitonin, eelcalcitonin, human calcitonin, porcine calcitonin, rat calcitonin orsalmon calcitonin provided by natural, synthetic, or geneticallyengineered sources.

As used herein, the term “calcitonin analog” means calcitonin whereinone or more of the amino acids have been replaced while retaining someor all of the activity of the calcitonin. The analog is described bynoting the replacement amino acids with the position of the replacementas a superscript followed by a description of the calcitonin. Forexample, “Pro² calcitonin, human” means that the glycine typically foundat the 2 position of a human calcitonin molecule has been replaced withproline.

Calcitonin analogs may be obtained by various means, as will beunderstood by those skilled in the art. For example, certain amino acidsmay be substituted for other amino acids in the calcitonin structurewithout appreciable loss of interactive binding capacity with structuressuch as, for example, antigen-binding regions of antibodies or bindingsites on substrate molecules. As the interactive capacity and nature ofcalcitonin defines its biological functional activity, certain aminoacid sequence substitutions can be made in the amino acid sequence andnevertheless remain a polypeptide with like properties.

In making such substitutions, the hydropathic index of amino acids maybe considered. The importance of the hydropathic amino acid index inconferring interactive biologic function on a polypeptide is generallyunderstood in the art. It is accepted that the relative hydropathiccharacter of the amino acid contributes to the secondary structure ofthe resultant polypeptide, which in turn defines the interaction of thepolypeptide with other molecules, for example, enzymes, substrates,receptors, DNA, antibodies, antigens, and the like. Each amino acid hasbeen assigned a hydropathic index on the basis of its hydrophobicity andcharge characteristics as follows: isoleucine (+4.5); valine (+4.2);leucine (+3.8); phenylalanine (+2.8); cysteine/cystine (+2.5);methionine (+1.9); alanine (+1.8); glycine (−0.4); threonine (−0.7);serine (−0.8); tryptophan (−0.9); tyrosine (−1.3); proline (−1.6);histidine (−3.2); glutamate (−3.5); glutamine (−3.5); aspartate (−3.5);asparagine (−3.5); lysine (−3.9); and arginine (−4.5). As will beunderstood by those skilled in the art, certain amino acids may besubstituted by other amino acids having a similar hydropathic index orscore and still result in a polypeptide with similar biologicalactivity, i.e., still obtain a biological functionally equivalentpolypeptide. In making such changes, the substitution of amino acidswhose hydropathic indices are within ±2 of each other is preferred,those which are within +1 of each other are particularly preferred, andthose within ±0.5 of each other are even more particularly preferred.

It is also understood in the art that the substitution of like aminoacids can be made effectively on the basis of hydrophilicity. U.S. Pat.No. 4,554,101 provides that the greatest local average hydrophilicity ofa protein, as governed by the hydrophilicity of its adjacent aminoacids, correlates with a biological property of the protein. As detailedin U.S. Pat. No. 4,554,101, the following hydrophilicity values havebeen assigned to amino acid residues: arginine (+3.0); lysine (±3.0);aspartate (+3.0±1); glutamate (+3.0±1); seine (+0.3); asparagine (+0.2);glutamine (+0.2); glycine (0); threonine (−0.4); proline (−0.5±1);alanine (−0.5); histidine (−0.5); cysteine (−1.0); methionine (−1.3);valine (−1.5); leucine (−1.8); isoleucine (−1.8); tyrosine (−2.3);phenylalanine (−2.5); tryptophan (−3.4). As is understood by thoseskilled in the art, an amino acid can be substituted for another havinga similar hydrophilicity value and still obtain a biologicallyequivalent, and in particular, an immunologically equivalentpolypeptide. In such changes, the substitution of amino acids whosehydrophilicity values are within ±2 of each other is preferred, thosewhich are within ±1 of each other are particularly preferred, and thosewithin ±0.5 of each other are even more particularly preferred.

As outlined above, amino acid substitutions are generally thereforebased on the relative similarity of the amino acid side-chainsubstituents, for example, their hydrophobicity, hydrophilicity, charge,size, and the like. Exemplary substitutions (i.e., amino acids that maybe interchanged without significantly altering the biological activityof the polypeptide) that take various of the foregoing characteristicsinto consideration are well known to those of skill in the art andinclude, for example: arginine and lysine; glutamate and aspartate;serine and threonine; glutamine and asparagine; and valine, leucine andisoleucine.

As used herein, the term “calcitonin fragment” means a segment of theamino acid sequence found in the calcitonin that retains some or all ofthe activity of the calcitonin.

As used herein, the term “calcitonin fragment analog” means a segment ofthe amino acid sequence found in the calcitonin molecule wherein one ormore of the amino acids in the segment have been replace while retainingsome or all of the activity of the calcitonin.

As used herein, the term “PEG” refers to straight or branchedpolyethylene glycol polymers, and includes the monomethylether ofpolyethylene glycol (mPEG). The terms “PEG subunit” and polyethyleneglycol subunit refer to a single polyethylene glycol unit, i.e.,—(CH₂CH₂O)—.

As used herein, the term “lipophilic” means the ability to dissolve inlipids and/or the ability to penetrate, interact with and/or traversebiological membranes, and the term, “lipophilic moiety” or “lipophile”means a moiety which is lipophilic and/or which, when attached toanother chemical entity, increases the lipophilicity of such chemicalentity. Examples of lipophilic moieties include, but are not limited to,alkyls, fatty acids, esters of fatty acids, cholesteryl, adamantyl andthe like.

As used herein, the term “lower alkyl” refers to substituted orunsubstituted alkyl moieties having from 1 to 5 carbon atoms.

As used herein, the term “higher alkyl” refers to substituted orunsubstituted alkyl moieties having 6 or more carbon atoms.

In embodiments of the present invention, a substantially monodispersedmixture of calcitonin drug-oligomer conjugates is provided. Eachcalcitonin drug-oligomer conjugate in the monodispersed mixture includesa calcitonin drug coupled to an oligomer that comprises a polyethyleneglycol moiety. Preferably, at least about 96, 97, 98 or 99 percent ofthe conjugates in the mixture have the same molecular weight. Morepreferably, the mixture is a monodispersed mixture. Even morepreferably, the mixture is a substantially purely monodispersed mixture.Still more preferably, at least about 96, 97, 98 or 99 percent of theconjugates in the mixture have the same molecular weight and have thesame molecular structure. Most preferably, the mixture is a purelymonodispersed mixture.

The calcitonin drug is preferably calcitonin. More preferably, thecalcitonin drug is salmon calcitonin. However, it is to be understoodthat the calcitonin drug may be selected from various calcitonin drugsknown to those skilled in the art including, for example, calcitoninprecursor peptides, calcitonin, calcitonin analogs, calcitoninfragments, and calcitonin fragment analogs. Calcitonin precursorpeptides include, but are not limited to, katacalcin (PDN-21)(C-procalcitonin), and N-proCT (amino-terminal procalcitonin cleavagepeptide), human. Calcitonin analogs may be provided by substitution ofone or more amino acids in calcitonin as described above. Calcitoninfragments include, but are not limited to, calcitonin 1–7, human; andcalcitonin 8–32, salmon. Calcitonin fragment analogs may be provided bysubstitution of one or more of the amino acids in a calcitonin fragmentas described above.

The oligomer may be various oligomers comprising a polyethylene glycolmoiety as will be understood by those skilled in the art. Preferably,the polyethylene glycol moiety of the oligomer has at least 2, 3 or 4polyethylene glycol subunits. More preferably, the polyethylene glycolmoiety has at least 5 or 6 polyethylene glycol subunits and, mostpreferably, the polyethylene glycol moiety has at least 7 polyethyleneglycol subunits.

The oligomer may comprise one or more other moieties as will beunderstood by those skilled in the art including, but not limited to,additional hydrophilic moieties, lipophilic moieties, spacer moieties,linker moieties, and terminating moieties. The various moieties in theoligomer are covalently coupled to one another by either hydrolyzable ornon-hydrolyzable bonds.

The oligomer may further comprise one or more additional hydrophilicmoieties (i.e., moieties in addition to the polyethylene glycol moiety)including, but not limited to, sugars, polyalkylene oxides, andpolyamine/PEG copolymers. As polyethylene glycol is a polyalkyleneoxide, the additional hydrophilic moiety may be a polyethylene glycolmoiety. Adjacent polyethylene glycol moieties will be considered to bethe same moiety if they are coupled by an ether bond. For example, themoiety—O—C₂H₄—O—C₂H₄—O—C₂H₄—O—C₂H₄—O—C₂H₄—O—C₂H₄—is a single polyethylene glycol moiety having six polyethylene glycolsubunits. If this moiety were the only hydrophilic moiety in theoligomer, the oligomer would not contain an additional hydrophilicmoiety. Adjacent polyethylene glycol moieties will be considered to bedifferent moieties if they are coupled by a bond other than an etherbond. For example, the moiety

is a polyethylene glycol moiety having four polyethylene glycol subunitsand an additional hydrophilic moiety having two polyethylene glycolsubunits. Preferably, oligomers according to embodiments of the presentinvention comprise a polyethylene glycol moiety and no additionalhydrophilic moieties.

The oligomer may further comprise one or more lipophilic moieties aswill be understood by those skilled in the art. The lipophilic moiety ispreferably a saturated or unsaturated, linear or branched alkyl moietyor a saturated or unsaturated, linear or branched fatty acid moiety.When the lipophilic moiety is an alkyl moiety, it is preferably alinear, saturated or unsaturated alkyl moiety having 1 to 28 carbonatoms. More preferably, the alkyl moiety has 2 to 12 carbon atoms. Whenthe lipophilic moiety is a fatty acid moiety, it is preferably a naturalfatty acid moiety that is linear, saturated or unsaturated, having 2 to18 carbon atoms. More preferably, the fatty acid moiety has 3 to 14carbon atoms. Most preferably, the fatty acid moiety has at least 4, 5or 6 carbon atoms.

The oligomer may further comprise one or more spacer moieties as will beunderstood by those skilled in the art. Spacer moieties may, forexample, be used to separate a hydrophilic moiety from a lipophilicmoiety, to separate a lipophilic moiety or hydrophilic moiety from thecalcitonin drug, to separate a first hydrophilic or lipophilic moietyfrom a second hydrophilic or lipophilic moiety, or to separate ahydrophilic moiety or lipophilic moiety from a linker moiety. Spacermoieties are preferably selected from the group consisting of sugar,cholesterol and glycerine moieties.

The oligomer may further comprise one or more linker moieties that areused to couple the oligomer with the calcitonin drug as will beunderstood by those skilled in the art. Linker moieties are preferablyselected from the group consisting of alkyl and fatty acid moieties.

The oligomer may further comprise one or more terminating moieties atthe one or more ends of the oligomer which are not coupled to thecalcitonin drug. The terminating moiety is preferably an alkyl or alkoxymoiety, and is more preferably a lower alkyl or lower alkoxy moiety.Most preferably, the terminating moiety is methyl or methoxy. While theterminating moiety is preferably an alkyl or alkoxy moiety, it is to beunderstood that the terminating moiety may be various moieties as willbe understood by those skilled in the art including, but not limited to,sugars, cholesterol, alcohols, and fatty acids.

The oligomer is preferably covalently coupled to the calcitonin drug. Insome embodiments, the calcitonin drug is coupled to the oligomerutilizing a hydrolyzable bond (e.g., an ester or carbonate bond). Ahydrolyzable coupling may provide a calcitonin drug-oligomer conjugatethat acts as a prodrug. In certain instances, for example where thecalcitonin drug-oligomer conjugate is inactive (i.e., the conjugatelacks the ability to affect the body through the calcitonin drug'sprimary mechanism of action), a hydrolyzable coupling may provide for atime-release or controlled-release effect, administering the calcitonindrug over a given time period as one or more oligomers are cleaved fromtheir respective calcitonin drug-oligomer conjugates to provide theactive drug. In other embodiments, the calcitonin drug is coupled to theoligomer utilizing a non-hydrolyzable bond (e.g., a carbamate, amide, orether bond). Use of a non-hydrolyzable bond may be preferable when it isdesirable to allow the calcitonin drug-oligomer conjugate to circulatein the bloodstream for an extended period of time, preferably at least 2hours. When the oligomer is covalently coupled to the calcitonin drug,the oligomer further comprises one or more bonding moieties that areused to covalently couple the oligomer with the calcitonin drug as willbe understood by those skilled in the art. Bonding moieties arepreferably selected from the group consisting of covalent bond(s), estermoieties, carbonate moieties, carbamate moieties, amide moieties andsecondary amine moieties. More than one moiety on the oligomer may becovalently coupled to the calcitonin drug.

While the oligomer is preferably covalently coupled to the calcitonindrug, it is to be understood that the oligomer may be non-covalentlycoupled to the calcitonin drug to form a non-covalently conjugatedcalcitonin drug-oligomer complex. As will be understood by those skilledin the art, non-covalent couplings include, but are not limited to,hydrogen bonding, ionic bonding, Van der Waals bonding, and micellularor liposomal encapsulation. According to embodiments of the presentinvention, oligomers may be suitably constructed, modified and/orappropriately functionalized to impart the ability for non-covalentconjugation in a selected manner (e.g., to impart hydrogen bondingcapability), as will be understood by those skilled in the art.According to other embodiments of present invention, oligomers may bederivatized with various compounds including, but not limited to, aminoacids, oligopeptides, peptides, bile acids, bile acid derivatives, fattyacids, fatty acid derivatives, salicylic acids, salicylic acidderivatives, aminosalicylic acids, and aminosalicylic acid derivatives.The resulting oligomers can non-covalently couple (complex) with drugmolecules, pharmaceutical products, and/or pharmaceutical excipients.The resulting complexes preferably have balanced lipophilic andhydrophilic properties. According to still other embodiments of thepresent invention, oligomers may be derivatized with amine and/or alkylamines. Under suitable acidic conditions, the resulting oligomers canform non-covalently conjugated complexes with drug molecules,pharmaceutical products and/or pharmaceutical excipients. The productsresulting from such complexation preferably have balanced lipophilic andhydrophilic properties.

More than one oligomer (i.e., a plurality of oligomers) may be coupledto the calcitonin drug. The oligomers in the plurality are preferablythe same. However, it is to be understood that the oligomers in theplurality may be different from one another, or, alternatively, some ofthe oligomers in the plurality may be the same and some may bedifferent. When a plurality of oligomers are coupled to the calcitonindrug, it may be preferable to couple one or more of the oligomers to thecalcitonin drug with hydrolyzable bonds and couple one or more of theoligomers to the calcitonin drug with non-hydrolyzable bonds.Alternatively, all of the bonds coupling the plurality of oligomers tothe calcitonin drug may be hydrolyzable, but have varying degrees ofhydrolyzability such that, for example, one or more of the oligomers israpidly removed from the calcitonin drug by hydrolysis in the body andone or more of the oligomers is slowly removed from the calcitonin drugby hydrolysis in the body.

The oligomer may be coupled to the calcitonin drug at variousnucleophilic residues of the calcitonin drug including, but not limitedto, nucleophilic hydroxyl functions and/or amino functions. When thecalcitonin drug is a polypeptide, a nucleophilic hydroxyl function maybe found, for example, at serine and/or tyrosine residues, and anucleophilic amino function may be found, for example, at histidineand/or lysine residues, and/or at the one or more N-termini of thepolypeptide. When an oligomer is coupled to the one or more N-terminusof the calcitonin polypeptide, the coupling preferably forms a secondaryamine. When the calcitonin drug is salmon calcitonin, for example, theoligomer may be coupled to an amino functionality of the salmoncalcitonin, including the amino functionality of Lys¹¹, Lys¹⁸ and/or theN-terminus. While one or more oligomers may be coupled to the salmoncalcitonin, a higher bioefficacy, such as improved serum calciumlowering ability, is observed for the di-conjugated salmon calcitoninwhere an oligomer is coupled to the amino functionalities of Lys¹¹ andthe Lys¹⁸.

Substantially monodispersed mixtures of calcitonin drug-oligomerconjugates of the present invention may be synthesized by variousmethods. For example, a substantially monodispersed mixture of oligomersconsisting of carboxylic acid and polyethylene glycol is synthesized bycontacting a substantially monodispersed mixture of carboxylic acid witha substantially monodispersed mixture of polyethylene glycol underconditions sufficient to provide a substantially monodispersed mixtureof oligomers. The oligomers of the substantially monodispersed mixtureare then activated so that they are capable of reacting with acalcitonin drug to provide a calcitonin drug-oligomer conjugate. Oneembodiment of a synthesis route for providing a substantiallymonodispersed mixture of oligomers is illustrated in FIG. 3 anddescribed in Examples 11–18 hereinbelow. Another embodiment of asynthesis route for providing a substantially monodispersed mixture ofoligomers is illustrated in FIG. 4 and described in Examples 19–24hereinbelow. Still another embodiment of a synthesis route for providinga substantially monodispersed mixture of oligomers is illustrated inFIG. 5 and described in Examples 25–29 hereinbelow. Yet anotherembodiment of a synthesis route for providing a substantiallymonodispersed mixture of oligomers is illustrated in FIG. 6 anddescribed in Examples 30–31 hereinbelow. Another embodiment of asynthesis route for providing a substantially monodispersed mixture ofoligomers is illustrated in FIG. 7 and described in Examples 32–37hereinbelow. Still another embodiment of a synthesis route for providinga substantially monodispersed mixture of oligomers is illustrated inFIG. 8 and described in Example 38 hereinbelow. Yet another embodimentof a synthesis route for providing a substantially monodispersed mixtureof oligomers is illustrated in FIG. 9 and described in Example 39hereinbelow. Another embodiment of a synthesis route for providing asubstantially monodispersed mixture of oligomers is illustrated in FIG.10 and described in Example 40 hereinbelow.

The substantially monodispersed mixture of activated oligomers may bereacted with a substantially monodispersed mixture of calcitonin drugsunder conditions sufficient to provide a mixture of calcitonindrug-oligomer conjugates. A preferred synthesis is described in Example41 hereinbelow. As will be understood by those skilled in the art, thereaction conditions (e.g., selected molar ratios, solvent mixturesand/or pH) may be controlled such that the mixture of calcitonindrug-oligomer conjugates resulting from the reaction of thesubstantially monodispersed mixture of activated oligomers and thesubstantially monodispersed mixture of calcitonin drugs is asubstantially monodispersed mixture. For example, conjugation at theamino functionality of lysine may be suppressed by maintaining the pH ofthe reaction solution below the pK_(a) of lysine. Alternatively, themixture of calcitonin drug-oligomer conjugates may be separated andisolated utilizing, for example, HPLC to provide a substantiallymonodispersed mixture of calcitonin drug-oligomer conjugates, forexample mono-, di-, or tri-conjugates. The degree of conjugation (e.g.,whether the isolated molecule is a mono-, di-, or tri-conjugate) of aparticular isolated conjugate may be determined and/or verifiedutilizing various techniques as will be understood by those skilled inthe art including, but not limited to, mass spectroscopy. The particularconjugate structure (e.g., whether the oligomer is at Lys¹¹, Lys¹⁸ orthe N-terminus of a salmon calcitonin monoconjugate) may be determinedand/or verified utilizing various techniques as will be understood bythose skilled in the art including, but not limited to, sequenceanalysis, peptide mapping, selective enzymatic cleavage, and/orendopeptidase cleavage.

As will be understood by those skilled in the art, one or more of thereaction sites on the calcitonin drug may be blocked by, for example,reacting the calcitonin drug with a suitable blocking reagent such asN-tert-butoxycarbonyl (t-BOC), or N-(9-fluorenylmethoxycarbonyl)(N-FMOC). This process may be preferred, for example, when thecalcitonin drug is a polypeptide and it is desired to form anunsaturated conjugate (i.e., a conjugate wherein not all nucleophilicresidues are conjugated) having an oligomer at the N-terminus of thepolypeptide. Following such blocking, the substantially monodispersedmixture of blocked calcitonin drugs may be reacted with thesubstantially monodispersed mixture of activated oligomers to provide amixture of calcitonin drug-oligomer conjugates having oligomer(s)coupled to one or more nucleophilic residues and having blockingmoieties coupled to other nucleophilic residues. After the conjugationreaction, the calcitonin drug-oligomer conjugates may be de-blocked aswill be understood by those skilled in the art. If necessary, themixture of calcitonin drug-oligomer conjugates may then be separated asdescribed above to provide a substantially monodispersed mixture ofcalcitonin drug-oligomer conjugates. Alternatively, the mixture ofcalcitonin drug-oligomer conjugates may be separated prior tode-blocking.

Substantially monodispersed mixtures of calcitonin drug-oligomerconjugates according to embodiments of the present invention preferablyhave improved properties when compared with those of conventionalmixtures. For example, a substantially monodispersed mixture ofcalcitonin-oligomer conjugates preferably is capable of lowering serumcalcium levels by at least 5 percent. Preferably, the mixture ofconjugates is capable of lowering serum calcium levels by at least 10,11, 12, 13 or 14 percent. More preferably, the mixture of conjugates iscapable of lowering serum calcium levels by at least 15, 16, 17, 18 or19 percent, and, most preferably, the mixture of conjugates is capableof lowering serum calcium levels by at least 20 percent.

As another example, a substantially monodispersed mixture ofcalcitonin-oligomer conjugates preferably has an increased resistance todegradation by chymotrypsin and/or trypsin when compared to theresistance to degradation by chymotrypsin and/or trypsin, respectively,of the calcitonin drug which is not coupled to the oligomer. Resistanceto chymotrypsin or trypsin corresponds to the percent remaining when themolecule to be tested is digested in the applicable enzyme using theprocedure outlined in Example 51 below. Preferably, the resistance todegradation by chymotrypsin of the mixture of calcitonin drug-oligomerconjugates is about 10 percent greater than the resistance todegradation by chymotrypsin of the mixture of calcitonin drugs that isnot conjugated with the oligomer. More preferably, the resistance todegradation by chymotrypsin of the mixture of calcitonin drug-oligomerconjugates is about 15 percent greater than the resistance todegradation by chymotrypsin of the mixture of calcitonin drug that isnot conjugated with the oligomer, and, most preferably, the resistanceto degradation by chymotrypsin of the mixture of calcitonindrug-oligomer conjugates is about 20 percent greater than the resistanceto degradation by chymotrypsin of the mixture of calcitonin drug that isnot conjugated with the oligomer. Preferably, the resistance todegradation by trypsin of the mixture of calcitonin drug-oligomerconjugates is about 10 percent greater than the resistance todegradation by trypsin of the mixture of calcitonin drug that is notconjugated with the oligomer. More preferably, the resistance todegradation by trypsin of the mixture of calcitonin drug-oligomerconjugates is about 20 percent greater than the resistance todegradation by trypsin of the mixture of calcitonin drug that is notconjugated with the oligomer, and, most preferably, the resistance todegradation by trypsin of the mixture of calcitonin drug-oligomerconjugates is about 30 percent greater than the resistance todegradation by trypsin of the mixture of calcitonin drug that is notconjugated with the oligomer.

As still another example, a substantially monodispersed mixture ofcalcitonin-oligomer conjugates preferably has a higher bioefficacy thanthe bioefficacy of the calcitonin drug which is not coupled to theoligomer. The bioefficacy of a particular compound corresponds to itsarea-under-the-curve (AUC) value. Preferably, the bioefficacy of themixture is about 5 percent greater than the bioefficacy of thecalcitonin drug which is not coupled to the oligomer. More preferably,the bioefficacy of the mixture is about 10 percent greater than thebioefficacy of the calcitonin drug which is not coupled to the oligomer.

As yet another example, a substantially monodispersed mixture ofcalcitonin-oligomer conjugates preferably has an in vivo activity thatis greater than the in vivo activity of a polydispersed mixture ofcalcitonin drug-oligomer conjugates having the same number averagemolecular weight as the substantially monodispersed mixture. As will beunderstood by those skilled in the art, the number average molecularweight of a mixture may be measured by various methods including, butnot limited to, size exclusion chromatography such as gel permeationchromatography as described, for example, in H. R. Allcock & F. W.Lampe, CONTEMPORARY POLYMER CHEMISTRY 394–402 (2d. ed., 1991).

As another example, a substantially monodispersed mixture ofcalcitonin-oligomer conjugates preferably has an in vitro activity thatis greater than the in vitro activity of a polydispersed mixture ofcalcitonin drug-oligomer conjugates having the same number averagemolecular weight as the substantially monodispersed mixture. As will beunderstood by those skilled in the art, the number average molecularweight of a mixture may be measured by various methods including, butnot limited to, size exclusion chromatography.

As still another example, a substantially monodispersed mixture ofcalcitonin-oligomer conjugates preferably has an increased resistance todegradation by chymotrypsin and/or trypsin when compared to theresistance to degradation by chymotrypsin and/or trypsin of apolydispersed mixture of calcitonin drug-oligomer conjugates having thesame number average molecular weight as the substantially monodispersedmixture. As will be understood by those skilled in the art, the numberaverage molecular weight of a mixture may be measured by various methodsincluding, but not limited to, size exclusion chromatography.

As yet another example, a substantially monodispersed mixture ofcalcitonin-oligomer conjugates preferably has an inter-subjectvariability that is less than the inter-subject variability of apolydispersed mixture of calcitonin drug-oligomer conjugates having thesame number average molecular weight as the substantially monodispersedmixture. As will be understood by those skilled in the art, the numberaverage molecular weight of a mixture may be measured by various methodsincluding, but not limited to, size exclusion chromatography. Theinter-subject variability may be measured by various methods, as will beunderstood by those skilled in the art. The inter-subject variability ispreferably calculated as follows. The area under a dose response curve(AUC) (i.e., the area between the dose-response curve and a baselinevalue) is determined for each subject. The average AUC for all subjectsis determined by summing the AUCs of each subject and dividing the sumby the number of subjects. The absolute value of the difference betweenthe subject's AUC and the average AUC is then determined for eachsubject. The absolute values of the differences obtained are then summedto give a value that represents the inter-subject variability. Lowervalues represent lower inter-subject variabilities and higher valuesrepresent higher inter-subject variabilities.

Substantially monodispersed mixtures of calcitonin drug-oligomerconjugates according to embodiments of the present invention preferablyhave two or more of the above-described improved properties. Morepreferably, substantially monodispersed mixtures of calcitonindrug-oligomer conjugates according to embodiments of the presentinvention have three or more of the above-described improved properties.Most preferably, substantially monodispersed mixtures of calcitonindrug-oligomer conjugates according to embodiments of the presentinvention have four or more of the above-described improved properties.

In still other embodiments according to the present invention, a mixtureof conjugates having a molecular weight distribution with a standarddeviation of less than about 22 Daltons is provided. Each conjugate inthe mixture includes a calcitonin drug coupled to an oligomer thatcomprises a polyethylene glycol moiety. The standard deviation ispreferably less than about 14 Daltons and is more preferably less thanabout 11 Daltons. The molecular weight distribution may be determined bymethods known to those skilled in the art including, but not limited to,size exclusion chromatography such as gel permeation chromatography asdescribed, for example, in H. R. Allcock & F. W. Lampe, CONTEMPORARYPOLYMER CHEMISTRY 394–402 (2d. ed., 1991). The standard deviation of themolecular weight distribution may then be determined by statisticalmethods as will be understood by those skilled in the art.

The calcitonin drug is preferably calcitonin. More preferably, thecalcitonin drug is salmon calcitonin. However, it is to be understoodthat the calcitonin drug may be selected from various calcitonin drugsknown to those skilled in the art including, for example, calcitoninprecursor peptides, calcitonin, calcitonin analogs, calcitoninfragments, and calcitonin fragment analogs. Calcitonin precursorpeptides include, but are not limited to, katacalcin (PDN-21)(C-procalcitonin), and N-proCT (amino-terminal procalcitonin cleavagepeptide), human. Calcitonin analogs may be provided by substitution ofone or more amino acids in calcitonin as described above. Calcitoninfragments include, but are not limited to, calcitonin 1–7, human; andcalcitonin 8–32, salmon. Calcitonin fragment analogs may be provided bysubstitution of one or more of the amino acids in a calcitonin fragmentas described above.

The oligomer may be various oligomers comprising a polyethylene glycolmoiety as will be understood by those skilled in the art. Preferably,the polyethylene glycol moiety of the oligomer has at least 2, 3 or 4polyethylene glycol subunits. More preferably, the polyethylene glycolmoiety has at least 5 or 6 polyethylene glycol subunits and, mostpreferably, the polyethylene glycol moiety has at least 7 polyethyleneglycol subunits.

The oligomer may comprise one or more other moieties as will beunderstood by those skilled in the art including, but not limited to,additional hydrophilic moieties, lipophilic moieties, spacer moieties,linker moieties, and terminating moieties. The various moieties in theoligomer are covalently coupled to one another by either hydrolyzable ornon-hydrolyzable bonds.

The oligomer may further comprise one or more additional hydrophilicmoieties (i.e., moieties in addition to the polyethylene glycol moiety)including, but not limited to, sugars, polyalkylene oxides, andpolyamine/PEG copolymers. As polyethylene glycol is a polyalkyleneoxide, the additional hydrophilic moiety may be a polyethylene glycolmoiety. Adjacent polyethylene glycol moieties will be considered to bethe same moiety if they are coupled by an ether bond. For example, themoiety—O—C₂H₄—O—C₂H₄—O—C₂H₄—O —C₂H₄—O—C₂H₄—O—C₂H₄—is a single polyethylene glycol moiety having six polyethylene glycolsubunits. If this moiety were the only hydrophilic moiety in theoligomer, the oligomer would not contain an additional hydrophilicmoiety. Adjacent polyethylene glycol moieties will be considered to bedifferent moieties if they are coupled by a bond other than an etherbond. For example, the moiety

is a polyethylene glycol moiety having four polyethylene glycol subunitsand an additional hydrophilic moiety having two polyethylene glycolsubunits. Preferably, oligomers according to embodiments of the presentinvention comprise a polyethylene glycol moiety and no additionalhydrophilic moieties.

The oligomer may further comprise one or more lipophilic moieties aswill be understood by those skilled in the art. The lipophilic moiety ispreferably a saturated or unsaturated, linear or branched alkyl moietyor a saturated or unsaturated, linear or branched fatty acid moiety.When the lipophilic moiety is an alkyl moiety, it is preferably alinear, saturated or unsaturated alkyl moiety having 1 to 28 carbonatoms. More preferably, the alkyl moiety has 2 to 12 carbon atoms. Whenthe lipophilic moiety is a fatty acid moiety, it is preferably a naturalfatty acid moiety that is linear, saturated or unsaturated, having 2 to18 carbon atoms. More preferably, the fatty acid moiety has 3 to 14carbon atoms. Most preferably, the fatty acid moiety has at least 4, 5or 6 carbon atoms.

The oligomer may further comprise one or more spacer moieties as will beunderstood by those skilled in the art. Spacer moieties may, forexample, be used to separate a hydrophilic moiety from a lipophilicmoiety, to separate a lipophilic moiety or hydrophilic moiety from thecalcitonin drug, to separate a first hydrophilic or lipophilic moietyfrom a second hydrophilic or lipophilic moiety, or to separate ahydrophilic moiety or lipophilic moiety from a linker moiety. Spacermoieties are preferably selected from the group consisting of sugar,cholesterol and glycerine moieties.

The oligomer may further comprise one or more linker moieties that areused to couple the oligomer with the calcitonin drug as will beunderstood by those skilled in the art. Linker moieties are preferablyselected from the group consisting of alkyl and fatty acid moieties.

The oligomer may further comprise one or more terminating moieties atthe one or more ends of the oligomer which are not coupled to thecalcitonin drug. The terminating moiety is preferably an alkyl or alkoxymoiety, and is more preferably a lower alkyl or lower alkoxy moiety.Most preferably, the terminating moiety is methyl or methoxy. While theterminating moiety is preferably an alkyl or alkoxy moiety, it is to beunderstood that the terminating moiety may be various moieties as willbe understood by those skilled in the art including, but not limited to,sugars, cholesterol, alcohols, and fatty acids.

The oligomer is preferably covalently coupled to the calcitonin drug. Insome embodiments, the calcitonin drug is coupled to the oligomerutilizing a hydrolyzable bond (e.g., an ester or carbonate bond). Ahydrolyzable coupling may provide a calcitonin drug-oligomer conjugatethat acts as a prodrug. In certain instances, for example where thecalcitonin drug-oligomer conjugate is inactive (i.e., the conjugatelacks the ability to affect the body through the calcitonin drug'sprimary mechanism of action), a hydrolyzable coupling may provide for atime-release or controlled-release effect, administering the calcitonindrug over a given time period as one or more oligomers are cleaved fromtheir respective calcitonin drug-oligomer conjugates to provide theactive drug. In other embodiments, the calcitonin drug is coupled to theoligomer utilizing a non-hydrolyzable bond (e.g., a carbamate, amide, orether bond). Use of a non-hydrolyzable bond may be preferable when it isdesirable to allow the calcitonin drug-oligomer conjugate to circulatein the bloodstream for an extended period of time, preferably at least 2hours. When the oligomer is covalently coupled to the calcitonin drug,the oligomer further comprises one or more bonding moieties that areused to covalently couple the oligomer with the calcitonin drug as willbe understood by those skilled in the art. Bonding moieties arepreferably selected from the group consisting of covalent bond(s), estermoieties, carbonate moieties, carbamate moieties, amide moieties andsecondary amine moieties. More than one moiety on the oligomer may becovalently coupled to the calcitonin drug.

While the oligomer is preferably covalently coupled to the calcitonindrug, it is to be understood that the oligomer may be non-covalentlycoupled to the calcitonin drug to form a non-covalently conjugatedcalcitonin drug-oligomer complex. As will be understood by those skilledin the art, non-covalent couplings include, but are not limited to,hydrogen bonding, ionic bonding, Van der Waals bonding, and micellularor liposomal encapsulation. According to embodiments of the presentinvention, oligomers may be suitably constructed, modified and/orappropriately functionalized to impart the ability for non-covalentconjugation in a selected manner (e.g., to impart hydrogen bondingcapability), as will be understood by those skilled in the art.According to other embodiments of present invention, oligomers may bederivatized with various compounds including, but not limited to, aminoacids, oligopeptides, peptides, bile acids, bile acid derivatives, fattyacids, fatty acid derivatives, salicylic acids, salicylic acidderivatives, aminosalicylic acids, and aminosalicylic acid derivatives.The resulting oligomers can non-covalently couple (complex) with drugmolecules, pharmaceutical products, and/or pharmaceutical excipients.The resulting complexes preferably have balanced lipophilic andhydrophilic properties. According to still other embodiments of thepresent invention, oligomers may be derivatized with amine and/or alkylamines. Under suitable acidic conditions, the resulting oligomers canform non-covalently conjugated complexes with drug molecules,pharmaceutical products and/or pharmaceutical excipients. The productsresulting from such complexation preferably have balanced lipophilic andhydrophilic properties.

More than one oligomer (i.e., a plurality of oligomers) may be coupledto the calcitonin drug. The oligomers in the plurality are preferablythe same. However, it is to be understood that the oligomers in theplurality may be different from one another, or, alternatively, some ofthe oligomers in the plurality may be the same and some may bedifferent. When a plurality of oligomers are coupled to the calcitonindrug, it may be preferable to couple one or more of the oligomers to thecalcitonin drug with hydrolyzable bonds and couple one or more of theoligomers to the calcitonin drug with non-hydrolyzable bonds.Alternatively, all of the bonds coupling the plurality of oligomers tothe calcitonin drug may be hydrolyzable, but have varying degrees ofhydrolyzability such that, for example, one or more of the oligomers israpidly removed from the calcitonin drug by hydrolysis in the body andone or more of the oligomers is slowly removed from the calcitonin drugby hydrolysis in the body.

The oligomer may be coupled to the calcitonin drug at variousnucleophilic residues of the calcitonin drug including, but not limitedto, nucleophilic hydroxyl functions and/or amino functions. When thecalcitonin drug is a polypeptide, a nucleophilic hydroxyl function maybe found, for example, at serine and/or tyrosine residues, and anucleophilic amino function may be found, for example, at histidineand/or lysine residues, and/or at the one or more N-termini of thepolypeptide. When an oligomer is coupled to the one or more N-terminusof the calcitonin polypeptide, the coupling preferably forms a secondaryamine.

When the calcitonin drug is salmon calcitonin, for example, the oligomermay be coupled to an amino functionality of the salmon calcitonin,including the amino functionality of Lys¹¹, Lys¹⁸ and/or the N-terminus.While one or more oligomers may be coupled to the salmon calcitonin, ahigher bioefficacy, such as improved serum calcium lowering ability, isobserved for the di-conjugated salmon calcitonin where an oligomer iscoupled to the amino functionalities of Lys¹¹ and the Lys¹⁸.

Mixtures of calcitonin drug-oligomer conjugates having a molecularweight distribution with a standard deviation of less than about 22Daltons may be synthesized by various methods. For example, a mixture ofoligomers having a molecular weight distribution with a standarddeviation of less than about 22 Daltons consisting of carboxylic acidand polyethylene glycol is synthesized by contacting a mixture ofcarboxylic acid having a molecular weight distribution with a standarddeviation of less than about 22 Daltons with a mixture of polyethyleneglycol having a molecular weight distribution with a standard deviationof less than about 22 Daltons under conditions sufficient to provide amixture of oligomers having a molecular weight distribution with astandard deviation of less than about 22 Daltons. The oligomers of themixture having a molecular weight distribution with a standard deviationof less than about 22 Daltons are then activated so that they arecapable of reacting with a calcitonin drug to provide a calcitonindrug-oligomer conjugate. One embodiment of a synthesis route forproviding a mixture of activated oligomers having a molecular weightdistribution with a standard deviation of less than about 22 Daltons isillustrated in FIG. 3 and described in Examples 11–18 hereinbelow.Another embodiment of a synthesis route for providing a mixture ofactivated oligomers having a molecular weight distribution with astandard deviation of less than about 22 Daltons is illustrated in FIG.4 and described in Examples 19–24 hereinbelow. Still another embodimentof a synthesis route for providing a mixture of activated oligomershaving a molecular weight distribution with a standard deviation of lessthan about 22 Daltons is illustrated in FIG. 5 and described in Examples25–29 hereinbelow. Yet another embodiment of a synthesis route forproviding a mixture of activated oligomers having a molecular weightdistribution with a standard deviation of less than about 22 Daltons isillustrated in FIG. 6 and described in Examples 30–31 hereinbelow.Another embodiment of a synthesis route for providing a mixture ofactivated oligomers having a molecular weight distribution with astandard deviation of less than about 22 Daltons is illustrated in FIG.7 and described in Examples 32–37 hereinbelow. Still another embodimentof a synthesis route for providing a mixture of activated oligomershaving a molecular weight distribution with a standard deviation of lessthan about 22 Daltons is illustrated in FIG. 8 and described in Example38 hereinbelow. Yet another embodiment of a synthesis route forproviding a mixture of activated oligomers having a molecular weightdistribution with a standard deviation of less than about 22 Daltons isillustrated in FIG. 9 and described in Example 39 hereinbelow. Anotherembodiment of a synthesis route for providing a mixture of activatedoligomers having a molecular weight distribution with a standarddeviation of less than about 22 Daltons is illustrated in FIG. 10 anddescribed in Example 40 hereinbelow.

The mixture of activated oligomers having a molecular weightdistribution with a standard deviation of less than about 22 Daltons isreacted with a mixture of calcitonin drugs having a molecular weightdistribution with a standard deviation of less than about 22 Daltonsunder conditions sufficient to provide a mixture of calcitonindrug-oligomer conjugates. A preferred synthesis is described in Example41 hereinbelow. As will be understood by those skilled in the art, thereaction conditions (e.g., selected molar ratios, solvent mixturesand/or pH) may be controlled such that the mixture of calcitonindrug-oligomer conjugates resulting from the reaction of the mixture ofactivated oligomers having a molecular weight distribution with astandard deviation of less than about 22 Daltons and the mixture ofcalcitonin drugs having a molecular weight distribution with a standarddeviation of less than about 22 Daltons is a mixture having a molecularweight distribution with a standard deviation of less than about 22Daltons. For example, conjugation at the amino functionality of lysinemay be suppressed by maintaining the pH of the reaction solution belowthe pK_(a) of lysine. Alternatively, the mixture of calcitonindrug-oligomer conjugates may be separated and isolated utilizing, forexample, HPLC to provide a mixture of calcitonin drug-oligomerconjugates, for example mono-, di-, or tri-conjugates, having amolecular weight distribution with a standard deviation of less thanabout 22 Daltons. The degree of conjugation (e.g., whether the isolatedmolecule is a mono-, di-, or tri-conjugate) of a particular isolatedconjugate may be determined and/or verified utilizing various techniquesas will be understood by those skilled in the art including, but notlimited to, mass spectroscopy. The particular conjugate structure (e.g.,whether the oligomer is at Lys¹¹, Lys¹⁸ or the N-terminus of a salmoncalcitonin monoconjugate) may be determined and/or verified utilizingvarious techniques as will be understood by those skilled in the artincluding, but not limited to, sequence analysis, peptide mapping,selective enzymatic cleavage, and/or endopeptidase cleavage.

As will be understood by those skilled in the art, one or more of thereaction sites on the calcitonin drug may be blocked by, for example,reacting the calcitonin drug with a suitable blocking reagent such asN-tert-butoxycarbonyl (t-BOC), or N-(9-fluorenylmethoxycarbonyl)(N-FMOC). This process may be preferred, for example, when thecalcitonin drug is a polypeptide and it is desired to form anunsaturated conjugate (i.e., a conjugate wherein not all nucleophilicresidues are conjugated) having an oligomer at the N-terminus of thepolypeptide. Following such blocking, the mixture of blocked calcitonindrugs having a molecular weight distribution with a standard deviationof less than about 22 Daltons may be reacted with the mixture ofactivated oligomers having a molecular weight distribution with astandard deviation of less than about 22 Daltons to provide a mixture ofcalcitonin drug-oligomer conjugates having oligomer(s) coupled to one ormore nucleophilic residues and having blocking moieties coupled to othernucleophilic residues. After the conjugation reaction, the calcitonindrug-oligomer conjugates may be de-blocked as will be understood bythose skilled in the art. If necessary, the mixture of calcitonindrug-oligomer conjugates may then be separated as described above toprovide a mixture of calcitonin drug-oligomer conjugates having amolecular weight distribution with a standard deviation of less thanabout 22 Daltons. Alternatively, the mixture of calcitonin drug-oligomerconjugates may be separated prior to de-blocking.

Mixtures of calcitonin drug-oligomer conjugates having a molecularweight distribution with a standard deviation of less than about 22Daltons according to embodiments of the present invention preferablyhave improved properties when compared with those of conventionalmixtures. For example, a mixture of calcitonin drug-oligomer conjugateshaving a molecular weight distribution with a standard deviation of lessthan about 22 Daltons preferably is capable of lowering serum calciumlevels by at least 5 percent. Preferably, the mixture of conjugates iscapable of lowering serum calcium levels by at least 10, 11, 12, 13 or14 percent. More preferably, the mixture of conjugates is capable oflowering serum calcium levels by at least 15, 16, 17, 18 or 19 percent,and, most preferably, the mixture of conjugates is capable of loweringserum calcium levels by at least 20 percent.

As another example, a mixture of calcitonin drug-oligomer conjugateshaving a molecular weight distribution with a standard deviation of lessthan about 22 Daltons preferably has an increased resistance todegradation by chymotrypsin and/or trypsin when compared to theresistance to degradation by chymotrypsin and/or trypsin, respectively,of the calcitonin drug which is not coupled to the oligomer. Resistanceto chymotrypsin or trypsin corresponds to the percent remaining when themolecule to be tested is digested in the applicable enzyme using aprocedure similar to the one outlined in Example 51 below. Preferably,the resistance to degradation by chymotrypsin of the mixture ofcalcitonin drug-oligomer conjugates is about 10 percent greater than theresistance to degradation by chymotrypsin of the mixture of calcitonindrugs that is not conjugated with the oligomer. More preferably, theresistance to degradation by chymotrypsin of the mixture of calcitonindrug-oligomer conjugates is about 15 percent greater than the resistanceto degradation by chymotrypsin of the mixture of calcitonin drug that isnot conjugated with the oligomer, and, most preferably, the resistanceto degradation by chymotrypsin of the mixture of calcitonindrug-oligomer conjugates is about 20 percent greater than the resistanceto degradation by chymotrypsin of the mixture of calcitonin drug that isnot conjugated with the oligomer. Preferably, the resistance todegradation by trypsin of the mixture of calcitonin drug-oligomerconjugates is about 10 percent greater than the resistance todegradation by trypsin of the mixture of calcitonin drug that is notconjugated with the oligomer. More preferably, the resistance todegradation by trypsin of the mixture of calcitonin drug-oligomerconjugates is about 20 percent greater than the resistance todegradation by trypsin of the mixture of calcitonin drug that is notconjugated with the oligomer, and, most preferably, the resistance todegradation by trypsin of the mixture of calcitonin drug-oligomerconjugates is about 30 percent greater than the resistance todegradation by trypsin of the mixture of calcitonin drug that is notconjugated with the oligomer.

As still another example, a mixture of calcitonin drug-oligomerconjugates having a molecular weight distribution with a standarddeviation of less than about 22 Daltons preferably has a higherbioefficacy than the bioefficacy of the calcitonin drug which is notcoupled to the oligomer. The bioefficacy of a particular compoundcorresponds to its area-under-the-curve (AUC) value. Preferably, thebioefficacy of the mixture is about 5 percent greater than thebioefficacy of the calcitonin drug which is not coupled to the oligomer.More preferably, the bioefficacy of the mixture is about 10 percentgreater than the bioefficacy of the calcitonin drug which is not coupledto the oligomer.

As yet another example, a mixture of calcitonin drug-oligomer conjugateshaving a molecular weight distribution with a standard deviation of lessthan about 22 Daltons preferably has an in vivo activity that is greaterthan the in vivo activity of a polydispersed mixture of calcitonindrug-oligomer conjugates having the same number average molecular weightas the mixture of calcitonin drug-oligomer conjugates having a molecularweight distribution with a standard deviation of less than about 22Daltons. As will be understood by those skilled in the art, the numberaverage molecular weight of a mixture may be measured by various methodsincluding, but not limited to, size exclusion chromatography such as gelpermeation chromatography as described, for example, in H. R. Allcock &F. W. Lampe, CONTEMPORARY POLYMER CHEMISTRY 394–402 (2d. ed., 1991).

As another example, a mixture of calcitonin drug-oligomer conjugateshaving a molecular weight distribution with a standard deviation of lessthan about 22 Daltons preferably has an in vitro activity that isgreater than the in vitro activity of a polydispersed mixture ofcalcitonin drug-oligomer conjugates having the same number averagemolecular weight as the mixture of calcitonin drug-oligomer conjugateshaving a molecular weight distribution with a standard deviation of lessthan about 22 Daltons. As will be understood by those skilled in theart, the number average molecular weight of a mixture may be measured byvarious methods including, but not limited to, size exclusionchromatography.

As still another example, a mixture of calcitonin drug-oligomerconjugates having a molecular weight distribution with a standarddeviation of less than about 22 Daltons preferably has an increasedresistance to degradation by chymotrypsin and/or trypsin when comparedto the resistance to degradation by chymotrypsin and/or trypsin of apolydispersed mixture of calcitonin drug-oligomer conjugates having thesame number average molecular weight as the mixture of calcitonindrug-oligomer conjugates having a molecular weight distribution with astandard deviation of less than about 22 Daltons. As will be understoodby those skilled in the art, the number average molecular weight of amixture may be measured by various methods including, but not limitedto, size exclusion chromatography.

As yet another example, a mixture of calcitonin drug-oligomer conjugateshaving a molecular weight distribution with a standard deviation of lessthan about 22 Daltons preferably has an inter-subject variability thatis less than the inter-subject variability of a polydispersed mixture ofcalcitonin drug-oligomer conjugates having the same number averagemolecular weight as the mixture of calcitonin drug-oligomer conjugateshaving a molecular weight distribution with a standard deviation of lessthan about 22 Daltons. As will be understood by those skilled in theart, the number average molecular weight of a mixture may be measured byvarious methods including, but not limited to, size exclusionchromatography. The inter-subject variability may be measured by variousmethods, as will be understood by those skilled in the art. Theinter-subject variability is preferably calculated as follows. The areaunder a dose response curve (AUC) (i.e., the area between thedose-response curve and a baseline value) is determined for eachsubject. The average AUC for all subjects is determined by summing theAUCs of each subject and dividing the sum by the number of subjects. Theabsolute value of the difference between the subject's AUC and theaverage AUC is then determined for each subject. The absolute values ofthe differences obtained are then summed to give a value that representsthe inter-subject variability. Lower values represent lowerinter-subject variabilities and higher values represent higherinter-subject variabilities.

Mixtures of calcitonin drug-oligomer conjugates having a molecularweight distribution with a standard deviation of less than about 22Daltons according to embodiments of the present invention preferablyhave two or more of the above-described improved properties. Morepreferably, mixtures of calcitonin drug-oligomer conjugates having amolecular weight distribution with a standard deviation of less thanabout 22 Daltons according to embodiments of the present invention havethree or more of the above-described improved properties. Mostpreferably, mixtures of calcitonin drug-oligomer conjugates having amolecular weight distribution with a standard deviation of less thanabout 22 Daltons according to embodiments of the present invention havefour or more of the above-described improved properties.

According to yet other embodiments of the present invention, a mixtureof conjugates is provided where each conjugate includes a calcitonindrug coupled to an oligomer comprising a polyethylene glycol moiety, andthe mixture has a dispersity coefficient (DC) greater than 10,000 where

${DC} = \frac{( {\sum\limits_{i = 1}^{n}{N_{i}M_{i}}} )^{2}}{{\sum\limits_{i = 1}^{n}{N_{i}M_{i}^{2}{\sum\limits_{i = 1}^{n}N_{i}}}} - ( {\sum\limits_{i = 1}^{n}{N_{i}M_{i}}} )^{2}}$

wherein:

-   -   n is the number of different molecules in the sample;    -   N_(i) is the number of i^(th) molecules in the sample; and    -   M_(i) is the mass of the i^(th) molecule.        The mixture of conjugates preferably has a dispersity        coefficient greater than 100,000. More preferably, the        dispersity coefficient of the conjugate mixture is greater than        500,000 and, most preferably, the dispersity coefficient is        greater than 10,000,000. The variables n, N_(i), and M_(i) may        be determined by various methods as will be understood by those        skilled in the art, including, but not limited to, methods        described below in Example 49.

The calcitonin drug is preferably calcitonin. More preferably, thecalcitonin drug is salmon calcitonin. However, it is to be understoodthat the calcitonin drug may be selected from various calcitonin drugsknown to those skilled in the art including, for example, calcitoninprecursor peptides, calcitonin, calcitonin analogs, calcitoninfragments, and calcitonin fragment analogs. Calcitonin precursorpeptides include, but are not limited to, katacalcin (PDN-21)(C-procalcitonin), and N-proCT (amino-terminal procalcitonin cleavagepeptide), human. Calcitonin analogs may be provided by substitution ofone or more amino acids in calcitonin as described above. Calcitoninfragments include, but are not limited to, calcitonin 1–7, human; andcalcitonin 8–32, salmon. Calcitonin fragment analogs may be provided bysubstitution of one or more of the amino acids in a calcitonin fragmentas described above.

The oligomer may be various oligomers comprising a polyethylene glycolmoiety as will be understood by those skilled in the art. Preferably,the polyethylene glycol moiety of the oligomer has at least 2, 3 or 4polyethylene glycol subunits. More preferably, the polyethylene glycolmoiety has at least 5 or 6 polyethylene glycol subunits and, mostpreferably, the polyethylene glycol moiety has at least 7 polyethyleneglycol subunits.

The oligomer may comprise one or more other moieties as will beunderstood by those skilled in the art including, but not limited to,additional hydrophilic moieties, lipophilic moieties, spacer moieties,linker moieties, and terminating moieties. The various moieties in theoligomer are covalently coupled to one another by either hydrolyzable ornon-hydrolyzable bonds.

The oligomer may further comprise one or more additional hydrophilicmoieties (i.e., moieties in addition to the polyethylene glycol moiety)including, but not limited to, sugars, polyalkylene oxides, andpolyamine/PEG copolymers. As polyethylene glycol is a polyalkyleneoxide, the additional hydrophilic moiety may be a polyethylene glycolmoiety. Adjacent polyethylene glycol moieties will be considered to bethe same moiety if they are coupled by an ether bond. For example, themoiety—O—C₂H₄—O—C₂H₄—O—C₂H₄—O—C₂H₄—O—C₂H₄—O—C₂H₄—is a single polyethylene glycol moiety having six polyethylene glycolsubunits. If this moiety were the only hydrophilic moiety in theoligomer, the oligomer would not contain an additional hydrophilicmoiety. Adjacent polyethylene glycol moieties will be considered to bedifferent moieties if they are coupled by a bond other than an etherbond. For example, the moiety

is a polyethylene glycol moiety having four polyethylene glycol subunitsand an additional hydrophilic moiety having two polyethylene glycolsubunits. Preferably, oligomers according to embodiments of the presentinvention comprise a polyethylene glycol moiety and no additionalhydrophilic moieties.

The oligomer may further comprise one or more lipophilic moieties aswill be understood by those skilled in the art. The lipophilic moiety ispreferably a saturated or unsaturated, linear or branched alkyl moietyor a saturated or unsaturated, linear or branched fatty acid moiety.When the lipophilic moiety is an alkyl moiety, it is preferably alinear, saturated or unsaturated alkyl moiety having 1 to 28 carbonatoms. More preferably, the alkyl moiety has 2 to 12 carbon atoms. Whenthe lipophilic moiety is a fatty acid moiety, it is preferably a naturalfatty acid moiety that is linear, saturated or unsaturated, having 2 to18 carbon atoms. More preferably, the fatty acid moiety has 3 to 14carbon atoms. Most preferably, the fatty acid moiety has at least 4, 5or 6 carbon atoms.

The oligomer may further comprise one or more spacer moieties as will beunderstood by those skilled in the art. Spacer moieties may, forexample, be used to separate a hydrophilic moiety from a lipophilicmoiety, to separate a lipophilic moiety or hydrophilic moiety from thecalcitonin drug, to separate a first hydrophilic or lipophilic moietyfrom a second hydrophilic or lipophilic moiety, or to separate ahydrophilic moiety or lipophilic moiety from a linker moiety. Spacermoieties are preferably selected from the group consisting of sugar,cholesterol and glycerine moieties.

The oligomer may further comprise one or more linker moieties that areused to couple the oligomer with the calcitonin drug as will beunderstood by those skilled in the art. Linker moieties are preferablyselected from the group consisting of alkyl and fatty acid moieties.

The oligomer may further comprise one or more terminating moieties atthe one or more ends of the oligomer which are not coupled to thecalcitonin drug. The terminating moiety is preferably an alkyl or alkoxymoiety, and is more preferably a lower alkyl or lower alkoxy moiety.Most preferably, the terminating moiety is methyl or methoxy. While theterminating moiety is preferably an alkyl or alkoxy moiety, it is to beunderstood that the terminating moiety may be various moieties as willbe understood by those skilled in the art including, but not limited to,sugars, cholesterol, alcohols, and fatty acids.

The oligomer is preferably covalently coupled to the calcitonin drug. Insome embodiments, the calcitonin drug is coupled to the oligomerutilizing a hydrolyzable bond (e.g., an ester or carbonate bond). Ahydrolyzable coupling may provide a calcitonin drug-oligomer conjugatethat acts as a prodrug. In certain instances, for example where thecalcitonin drug-oligomer conjugate is inactive (i.e., the conjugatelacks the ability to affect the body through the calcitonin drug'sprimary mechanism of action), a hydrolyzable coupling may provide for atime-release or controlled-release effect, administering the calcitonindrug over a given time period as one or more oligomers are cleaved fromtheir respective calcitonin drug-oligomer conjugates to provide theactive drug. In other embodiments, the calcitonin drug is coupled to theoligomer utilizing a non-hydrolyzable bond (e.g., a carbamate, amide, orether bond). Use of a non-hydrolyzable bond may be preferable when it isdesirable to allow the calcitonin drug-oligomer conjugate to circulatein the bloodstream for an extended period of time, preferably at least 2hours. When the oligomer is covalently coupled to the calcitonin drug,the oligomer further comprises one or more bonding moieties that areused to covalently couple the oligomer with the calcitonin drug as willbe understood by those skilled in the art. Bonding moieties arepreferably selected from the group consisting of covalent bond(s), estermoieties, carbonate moieties, carbamate moieties, amide moieties andsecondary amine moieties. More than one moiety on the oligomer may becovalently coupled to the calcitonin drug.

While the oligomer is preferably covalently coupled to the calcitonindrug, it is to be understood that the oligomer may be non-covalentlycoupled to the calcitonin drug to form a non-covalently conjugatedcalcitonin drug-oligomer complex. As will be understood by those skilledin the art, non-covalent couplings include, but are not limited to,hydrogen bonding, ionic bonding, Van der Waals bonding, and micellularor liposomal encapsulation. According to embodiments of the presentinvention, oligomers may be suitably constructed, modified and/orappropriately functionalized to impart the ability for non-covalentconjugation in a selected manner (e.g., to impart hydrogen bondingcapability), as will be understood by those skilled in the art.According to other embodiments of present invention, oligomers may bederivatized with various compounds including, but not limited to, aminoacids, oligopeptides, peptides, bile acids, bile acid derivatives, fattyacids, fatty acid derivatives, salicylic acids, salicylic acidderivatives, aminosalicylic acids, and aminosalicylic acid derivatives.The resulting oligomers can non-covalently couple (complex) with drugmolecules, pharmaceutical products, and/or pharmaceutical excipients.The resulting complexes preferably have balanced lipophilic andhydrophilic properties. According to still other embodiments of thepresent invention, oligomers may be derivatized with amine and/or alkylamines. Under suitable acidic conditions, the resulting oligomers canform non-covalently conjugated complexes with drug molecules,pharmaceutical products and/or pharmaceutical excipients. The productsresulting from such complexation preferably have balanced lipophilic andhydrophilic properties.

More than one oligomer (i.e., a plurality of oligomers) may be coupledto the calcitonin drug. The oligomers in the plurality are preferablythe same. However, it is to be understood that the oligomers in theplurality may be different from one another, or, alternatively, some ofthe oligomers in the plurality may be the same and some may bedifferent. When a plurality of oligomers are coupled to the calcitonindrug, it may be preferable to couple one or more of the oligomers to thecalcitonin drug with hydrolyzable bonds and couple one or more of theoligomers to the calcitonin drug with non-hydrolyzable bonds.Alternatively, all of the bonds coupling the plurality of oligomers tothe calcitonin drug may be hydrolyzable, but have varying degrees ofhydrolyzability such that, for example, one or more of the oligomers israpidly removed from the calcitonin drug by hydrolysis in the body andone or more of the oligomers is slowly removed from the calcitonin drugby hydrolysis in the body.

The oligomer may be coupled to the calcitonin drug at variousnucleophilic residues of the calcitonin drug including, but not limitedto, nucleophilic hydroxyl functions and/or amino functions. When thecalcitonin drug is a polypeptide, a nucleophilic hydroxyl function maybe found, for example, at serine and/or tyrosine residues, and anucleophilic amino function may be found, for example, at histidineand/or lysine residues, and/or at the one or more N-termini of thepolypeptide. When an oligomer is coupled to the one or more N-terminusof the calcitonin polypeptide, the coupling preferably forms a secondaryamine. When the calcitonin drug is salmon calcitonin, for example, theoligomer may be coupled to an amino functionality of the salmoncalcitonin, including the amino functionality of Lys¹¹, Lys¹⁸ and/or theN-terminus. While one or more oligomers may be coupled to the salmoncalcitonin, a higher bioefficacy, such as improved serum calciumlowering ability, is observed for the di-conjugated salmon calcitoninwhere an oligomer is coupled to the amino functionalities of Lys¹¹ andthe Lys¹⁸.

Mixtures of calcitonin drug-oligomer conjugates having a dispersitycoefficient greater than 10,000 may be synthesized by various methods.For example, a mixture of oligomers having a dispersity coefficientgreater than 10,000 consisting of carboxylic acid and polyethyleneglycol is synthesized by contacting a mixture of carboxylic acid havinga dispersity coefficient greater than 10,000 with a mixture ofpolyethylene glycol having a dispersity coefficient greater than 10,000under conditions sufficient to provide a mixture of oligomers having adispersity coefficient greater than 10,000. The oligomers of the mixturehaving a dispersity coefficient greater than 10,000 are then activatedso that they are capable of reacting with a calcitonin drug to provide acalcitonin drug-oligomer conjugate. One embodiment of a synthesis routefor providing a mixture of activated oligomers having a dispersitycoefficient greater than 10,000 is illustrated in FIG. 3 and describedin Examples 11–18 hereinbelow. Another embodiment of a synthesis routefor providing a mixture of activated oligomers having a dispersitycoefficient greater than 10,000 is illustrated in FIG. 4 and describedin Examples 19–24 hereinbelow. Still another embodiment of a synthesisroute for providing a mixture of activated oligomers having a dispersitycoefficient greater than 10,000 is illustrated in FIG. 5 and describedin Examples 25–29 hereinbelow. Yet another embodiment of a synthesisroute for providing a mixture of activated oligomers having a dispersitycoefficient greater than 10,000 is illustrated in FIG. 6 and describedin Examples 30–31 hereinbelow. Another embodiment of a synthesis routefor providing a mixture of activated oligomers having a dispersitycoefficient greater than 10,000 is illustrated in FIG. 7 and describedin Examples 32–37 hereinbelow. Still another embodiment of a synthesisroute for providing a mixture of activated oligomers having a dispersitycoefficient greater than 10,000 is illustrated in FIG. 8 and describedin Example 38 hereinbelow. Yet another embodiment of a synthesis routefor providing a mixture of activated oligomers having a dispersitycoefficient greater than 10,000 is illustrated in FIG. 9 and describedin Example 39 hereinbelow. Another embodiment of a synthesis route forproviding a mixture of activated oligomers having a dispersitycoefficient greater than 10,000 is illustrated in FIG. 10 and describedin Example 40 hereinbelow.

The mixture of activated oligomers having a dispersity coefficientgreater than 10,000 is reacted with a mixture of calcitonin drugs havinga dispersity coefficient greater than 10,000 under conditions sufficientto provide a mixture of calcitonin drug-oligomer conjugates. A preferredsynthesis is described in Example 41 hereinbelow. As will be understoodby those skilled in the art, the reaction conditions (e.g., selectedmolar ratios, solvent mixtures and/or pH) may be controlled such thatthe mixture of calcitonin drug-oligomer conjugates resulting from thereaction of the mixture of activated oligomers having a dispersitycoefficient greater than 10,000 and the mixture of calcitonin drugshaving a dispersity coefficient greater than 10,000 is a mixture havinga dispersity coefficient greater than 10,000. For example, conjugationat the amino functionality of lysine may be suppressed by maintainingthe pH of the reaction solution below the pK_(a) of lysine.Alternatively, the mixture of calcitonin drug-oligomer conjugates may beseparated and isolated utilizing, for example, HPLC to provide a mixtureof calcitonin drug-oligomer conjugates, for example mono-, di-, ortri-conjugates, having a dispersity coefficient greater than 10,000. Thedegree of conjugation (e.g., whether the isolated molecule is a mono-,di-, or tri-conjugate) of a particular isolated conjugate may bedetermined and/or verified utilizing various techniques as will beunderstood by those skilled in the art including, but not limited to,mass spectroscopy. The particular conjugate structure (e.g., whether theoligomer is at Lys¹¹, Lys¹⁸ or the N-terminus of a salmon calcitoninmonoconjugate) may be determined and/or verified utilizing varioustechniques as will be understood by those skilled in the art including,but not limited to, sequence analysis, peptide mapping, selectiveenzymatic cleavage, and/or endopeptidase cleavage.

As will be understood by those skilled in the art, one or more of thereaction sites on the calcitonin drug may be blocked by, for example,reacting the calcitonin drug with a suitable blocking reagent such asN-tert-butoxycarbonyl (t-BOC), or N-(9-fluorenylmethoxycarbonyl)(N-FMOC). This process may be preferred, for example, when thecalcitonin drug is a polypeptide and it is desired to form anunsaturated conjugate (i.e., a conjugate wherein not all nucleophilicresidues are conjugated) having an oligomer at the N-terminus of thepolypeptide. Following such blocking, the mixture of blocked calcitonindrugs having a dispersity coefficient greater than 10,000 may be reactedwith the mixture of activated oligomers having a dispersity coefficientgreater than 10,000 to provide a mixture of calcitonin drug-oligomerconjugates having oligomer(s) coupled to one or more nucleophilicresidues and having blocking moieties coupled to other nucleophilicresidues. After the conjugation reaction, the calcitonin drug-oligomerconjugates may be de-blocked as will be understood by those skilled inthe art. If necessary, the mixture of calcitonin drug-oligomerconjugates may then be separated as described above to provide a mixtureof calcitonin drug-oligomer conjugates having a dispersity coefficientgreater than 10,000. Alternatively, the mixture of calcitonindrug-oligomer conjugates may be separated prior to de-blocking.

Mixtures of calcitonin drug-oligomer conjugates having a dispersitycoefficient greater than 10,000 according to embodiments of the presentinvention preferably have improved properties when compared with thoseof conventional mixtures. For example, a mixture of calcitonindrug-oligomer conjugates having a dispersity coefficient greater than10,000 preferably is capable of lowering serum calcium levels by atleast 5 percent. Preferably, the mixture of conjugates is capable oflowering serum calcium levels by at least 10, 11, 12, 13 or 14 percent.More preferably, the mixture of conjugates is capable of lowering serumcalcium levels by at least 15, 16, 17, 18 or 19 percent, and, mostpreferably, the mixture of conjugates is capable of lowering serumcalcium levels by at least 20 percent.

As another example, a mixture of calcitonin drug-oligomer conjugateshaving a dispersity coefficient greater than 10,000 preferably has anincreased resistance to degradation by chymotrypsin and/or trypsin whencompared to the resistance to degradation by chymotrypsin and/ortrypsin, respectively, of the calcitonin drug which is not coupled tothe oligomer. Resistance to chymotrypsin or trypsin corresponds to thepercent remaining when the molecule to be tested is digested in theapplicable enzyme using a procedure similar to the one outlined inExample 51 below. Preferably, the resistance to degradation bychymotrypsin of the mixture of calcitonin drug-oligomer conjugates isabout 10 percent greater than the resistance to degradation bychymotrypsin of the mixture of calcitonin drugs that is not conjugatedwith the oligomer. More preferably, the resistance to degradation bychymotrypsin of the mixture of calcitonin drug-oligomer conjugates isabout 15 percent greater than the resistance to degradation bychymotrypsin of the mixture of calcitonin drug that is not conjugatedwith the oligomer, and, most preferably, the resistance to degradationby chymotrypsin of the mixture of calcitonin drug-oligomer conjugates isabout 20 percent greater than the resistance to degradation bychymotrypsin of the mixture of calcitonin drug that is not conjugatedwith the oligomer. Preferably, the resistance to degradation by trypsinof the mixture of calcitonin drug-oligomer conjugates is about 10percent greater than the resistance to degradation by trypsin of themixture of calcitonin drug that is not conjugated with the oligomer.More preferably, the resistance to degradation by trypsin of the mixtureof calcitonin drug-oligomer conjugates is about 20 percent greater thanthe resistance to degradation by trypsin of the mixture of calcitonindrug that is not conjugated with the oligomer, and, most preferably, theresistance to degradation by trypsin of the mixture of calcitonindrug-oligomer conjugates is about 30 percent greater than the resistanceto degradation by trypsin of the mixture of calcitonin drug that is notconjugated with the oligomer.

As still another example, a mixture of calcitonin drug-oligomerconjugates having a dispersity coefficient greater than 10,000preferably has a higher bioefficacy than the bioefficacy of thecalcitonin drug which is not coupled to the oligomer. The bioefficacy ofa particular compound corresponds to its area-under-the-curve (AUC)value. Preferably, the bioefficacy of the mixture is about 5 percentgreater than the bioefficacy of the calcitonin drug which is not coupledto the oligomer. More preferably, the bioefficacy of the mixture isabout 10 percent greater than the bioefficacy of the calcitonin drugwhich is not coupled to the oligomer.

A yet another example, a mixture of calcitonin drug-oligomer conjugateshaving a dispersity coefficient greater than 10,000 preferably has an invivo activity that is greater than the in vivo activity of apolydispersed mixture of calcitonin drug-oligomer conjugates having thesame number average molecular weight as the mixture of calcitonindrug-oligomer conjugates having a dispersity coefficient greater than10,000. As will be understood by those skilled in the art, the numberaverage molecular weight of a mixture may be measured by various methodsincluding, but not limited to, size exclusion chromatography such as gelpermeation chromatography as described, for example, in H. R. Allcock &F. W. Lampe, CONTEMPORARY POLYMER CHEMISTRY 394–402 (2d. ed., 1991).

As another example, a mixture of calcitonin drug-oligomer conjugateshaving a dispersity coefficient greater than 10,000 preferably has an invitro activity that is greater than the in vitro activity of apolydispersed mixture of calcitonin drug-oligomer conjugates having thesame number average molecular weight as the mixture of calcitonindrug-oligomer conjugates having a dispersity coefficient greater than10,000. As will be understood by those skilled in the art, the numberaverage molecular weight of a mixture may be measured by various methodsincluding, but not limited to, size exclusion chromatography.

As still another example, a mixture of calcitonin drug-oligomerconjugates having a dispersity coefficient greater than 10,000preferably has an increased resistance to degradation by chymotrypsinand/or trypsin when compared to the resistance to degradation bychymotrypsin and/or trypsin of a polydispersed mixture of calcitonindrug-oligomer conjugates having the same number average molecular weightas the mixture of calcitonin drug-oligomer conjugates having adispersity coefficient greater than 10,000. As will be understood bythose skilled in the art, the number average molecular weight of amixture may be measured by various methods including, but not limitedto, size exclusion chromatography.

As yet another example, a mixture of calcitonin drug-oligomer conjugateshaving a dispersity coefficient greater than 10,000 preferably has aninter-subject variability that is less than the inter-subjectvariability of a polydispersed mixture of calcitonin drug-oligomerconjugates having the same number average molecular weight as themixture of calcitonin drug-oligomer conjugates having a dispersitycoefficient greater than 10,000. As will be understood by those skilledin the art, the number average molecular weight of a mixture may bemeasured by various methods including, but not limited to, sizeexclusion chromatography. The inter-subject variability may be measuredby various methods, as will be understood by those skilled in the art.The inter-subject variability is preferably calculated as follows. Thearea under a dose response curve (AUC) (i.e., the area between thedose-response curve and a baseline value) is determined for eachsubject. The average AUC for all subjects is determined by summing theAUCs of each subject and dividing the sum by the number of subjects. Theabsolute value of the difference between the subject's AUC and theaverage AUC is then determined for each subject. The absolute values ofthe differences obtained are then summed to give a value that representsthe inter-subject variability. Lower values represent lowerinter-subject variabilities and higher values represent higherinter-subject variabilities.

Mixtures of calcitonin drug-oligomer conjugates having a dispersitycoefficient greater than 10,000 according to embodiments of the presentinvention preferably have two or more of the above-described improvedproperties. More preferably, mixtures of calcitonin drug-oligomerconjugates having a dispersity coefficient greater than 10,000 accordingto embodiments of the present invention have three or more of theabove-described improved properties. Most preferably, mixtures ofcalcitonin drug-oligomer conjugates having a dispersity coefficientgreater than 10,000 according to embodiments of the present inventionhave four or more of the above-described improved properties.

According to other embodiments of the present invention, a mixture ofconjugates in which each conjugate includes a calcitonin drug coupled toan oligomer and has the same number of polyethylene glycol subunits isprovided.

The calcitonin drug is preferably calcitonin. More preferably, thecalcitonin drug is salmon calcitonin. However, it is to be understoodthat the calcitonin drug may be selected from various calcitonin drugsknown to those skilled in the art including, for example, calcitoninprecursor peptides, calcitonin, calcitonin analogs, calcitoninfragments, and calcitonin fragment analogs. Calcitonin precursorpeptides include, but are not limited to, katacalcin (PDN-21)(C-procalcitonin), and N-proCT (amino-terminal procalcitonin cleavagepeptide), human. Calcitonin analogs may be provided by substitution ofone or more amino acids in calcitonin as described above. Calcitoninfragments include, but are not limited to, calcitonin 1–7, human; andcalcitonin 8–32, salmon. Calcitonin fragment analogs may be provided bysubstitution of one or more of the amino acids in a calcitonin fragmentas described above.

The oligomer may be various oligomers comprising a polyethylene glycolmoiety as will be understood by those skilled in the art. Preferably,the polyethylene glycol moiety of the oligomer has at least 2, 3 or 4polyethylene glycol subunits. More preferably, the polyethylene glycolmoiety has at least 5 or 6 polyethylene glycol subunits and, mostpreferably, the polyethylene glycol moiety has at least 7 polyethyleneglycol subunits.

The oligomer may comprise one or more other moieties as will beunderstood by those skilled in the art including, but not limited to,additional hydrophilic moieties, lipophilic moieties, spacer moieties,linker moieties, and terminating moieties. The various moieties in theoligomer are covalently coupled to one another by either hydrolyzable ornon-hydrolyzable bonds.

The oligomer may further comprise one or more additional hydrophilicmoieties (i.e., moieties in addition to the polyethylene glycol moiety)including, but not limited to, sugars, polyalkylene oxides, andpolyamine/PEG copolymers. As polyethylene glycol is a polyalkyleneoxide, the additional hydrophilic moiety may be a polyethylene glycolmoiety. Adjacent polyethylene glycol moieties will be considered to bethe same moiety if they are coupled by an ether bond. For example, themoiety—O—C₂H₄—O—C₂H₄—O—C₂H₄—O—C₂H₄—O—C₂H₄—O—C₂H₄—is a single polyethylene glycol moiety having six polyethylene glycolsubunits. If this moiety were the only hydrophilic moiety in theoligomer, the oligomer would not contain an additional hydrophilicmoiety. Adjacent polyethylene glycol moieties will be considered to bedifferent moieties if they are coupled by a bond other than an etherbond. For example, the moiety

is a polyethylene glycol moiety having four polyethylene glycol subunitsand an additional hydrophilic moiety having two polyethylene glycolsubunits. Preferably, oligomers according to embodiments of the presentinvention comprise a polyethylene glycol moiety and no additionalhydrophilic moieties.

The oligomer may further comprise one or more lipophilic moieties aswill be understood by those skilled in the art. The lipophilic moiety ispreferably a saturated or unsaturated, linear or branched alkyl moietyor a saturated or unsaturated, linear or branched fatty acid moiety.When the lipophilic moiety is an alkyl moiety, it is preferably alinear, saturated or unsaturated alkyl moiety having 1 to 28 carbonatoms. More preferably, the alkyl moiety has 2 to 12 carbon atoms. Whenthe lipophilic moiety is a fatty acid moiety, it is preferably a naturalfatty acid moiety that is linear, saturated or unsaturated, having 2 to18 carbon atoms. More preferably, the fatty acid moiety has 3 to 14carbon atoms. Most preferably, the fatty acid moiety has at least 4, 5or 6 carbon atoms.

The oligomer may further comprise one or more spacer moieties as will beunderstood by those skilled in the art. Spacer moieties may, forexample, be used to separate a hydrophilic moiety from a lipophilicmoiety, to separate a lipophilic moiety or hydrophilic moiety from thecalcitonin drug, to separate a first hydrophilic or lipophilic moietyfrom a second hydrophilic or lipophilic moiety, or to separate ahydrophilic moiety or lipophilic moiety from a linker moiety. Spacermoieties are preferably selected from the group consisting of sugar,cholesterol and glycerine moieties.

The oligomer may further comprise one or more linker moieties that areused to couple the oligomer with the calcitonin drug as will beunderstood by those skilled in the art. Linker moieties are preferablyselected from the group consisting of alkyl and fatty acid moieties.

The oligomer may further comprise one or more terminating moieties atthe one or more ends of the oligomer which are not coupled to thecalcitonin drug. The terminating moiety is preferably an alkyl or alkoxymoiety, and is more preferably a lower alkyl or lower alkoxy moiety.Most preferably, the terminating moiety is methyl or methoxy. While theterminating moiety is preferably an alkyl or alkoxy moiety, it is to beunderstood that the terminating moiety may be various moieties as willbe understood by those skilled in the art including, but not limited to,sugars, cholesterol, alcohols, and fatty acids.

The oligomer is preferably covalently coupled to the calcitonin drug. Insome embodiments, the calcitonin drug is coupled to the oligomerutilizing a hydrolyzable bond (e.g., an ester or carbonate bond). Ahydrolyzable coupling may provide a calcitonin drug-oligomer conjugatethat acts as a prodrug. In certain instances, for example where thecalcitonin drug-oligomer conjugate is inactive (i.e., the conjugatelacks the ability to affect the body through the calcitonin drug'sprimary mechanism of action), a hydrolyzable coupling may provide for atime-release or controlled-release effect, administering the calcitonindrug over a given time period as one or more oligomers are cleaved fromtheir respective calcitonin drug-oligomer conjugates to provide theactive drug. In other embodiments, the calcitonin drug is coupled to theoligomer utilizing a non-hydrolyzable bond (e.g., a carbamate, amide, orether bond). Use of a non-hydrolyzable bond may be preferable when it isdesirable to allow the calcitonin drug-oligomer conjugate to circulatein the bloodstream for an extended period of time, preferably at least 2hours. When the oligomer is covalently coupled to the calcitonin drug,the oligomer further comprises one or more bonding moieties that areused to covalently couple the oligomer with the calcitonin drug as willbe understood by those skilled in the art. Bonding moieties arepreferably selected from the group consisting of covalent bond(s), estermoieties, carbonate moieties, carbamate moieties, amide moieties andsecondary amine moieties. More than one moiety on the oligomer may becovalently coupled to the calcitonin drug.

While the oligomer is preferably covalently coupled to the calcitonindrug, it is to be understood that the oligomer may be non-covalentlycoupled to the calcitonin drug to form a non-covalently conjugatedcalcitonin drug-oligomer complex. As will be understood by those skilledin the art, non-covalent couplings include, but are not limited to,hydrogen bonding, ionic bonding, Van der Waals bonding, and micellularor liposomal encapsulation. According to embodiments of the presentinvention, oligomers may be suitably constructed, modified and/orappropriately functionalized to impart the ability for non-covalentconjugation in a selected manner (e.g., to impart hydrogen bondingcapability), as will be understood by those skilled in the art.According to other embodiments of present invention, oligomers may bederivatized with various compounds including, but not limited to, aminoacids, oligopeptides, peptides, bile acids, bile acid derivatives, fattyacids, fatty acid derivatives, salicylic acids, salicylic acidderivatives, aminosalicylic acids, and aminosalicylic acid derivatives.The resulting oligomers can non-covalently couple (complex) with drugmolecules, pharmaceutical products, and/or pharmaceutical excipients.The resulting complexes preferably have balanced lipophilic andhydrophilic properties. According to still other embodiments of thepresent invention, oligomers may be derivatized with amine and/or alkylamines. Under suitable acidic conditions, the resulting oligomers canform non-covalently conjugated complexes with drug molecules,pharmaceutical products and/or pharmaceutical excipients. The productsresulting from such complexation preferably have balanced lipophilic andhydrophilic properties.

More than one oligomer (i.e., a plurality of oligomers) may be coupledto the calcitonin drug. The oligomers in the plurality are preferablythe same. However, it is to be understood that the oligomers in theplurality may be different from one another, or, alternatively, some ofthe oligomers in the plurality may be the same and some may bedifferent. When a plurality of oligomers are coupled to the calcitonindrug, it may be preferable to couple one or more of the oligomers to thecalcitonin drug with hydrolyzable bonds and couple one or more of theoligomers to the calcitonin drug with non-hydrolyzable bonds.Alternatively, all of the bonds coupling the plurality of oligomers tothe calcitonin drug may be hydrolyzable, but have varying degrees ofhydrolyzability such that, for example, one or more of the oligomers israpidly removed from the calcitonin drug by hydrolysis in the body andone or more of the oligomers is slowly removed from the calcitonin drugby hydrolysis in the body.

The oligomer may be coupled to the calcitonin drug at variousnucleophilic residues of the calcitonin drug including, but not limitedto, nucleophilic hydroxyl functions and/or amino functions. When thecalcitonin drug is a polypeptide, a nucleophilic hydroxyl function maybe found, for example, at serine and/or tyrosine residues, and anucleophilic amino function may be found, for example, at histidineand/or lysine residues, and/or at the one or more N-termini of thepolypeptide. When an oligomer is coupled to the one or more N-terminusof the calcitonin polypeptide, the coupling preferably forms a secondaryamine. When the calcitonin drug is salmon calcitonin, for example, theoligomer may be coupled to an amino functionality of the salmoncalcitonin, including the amino functionality of Lys¹¹, Lys¹⁸ and/or theN-terminus. While one or more oligomers may be coupled to the salmoncalcitonin, a higher bioefficacy, such as improved serum calciumlowering ability, is observed for the di-conjugated salmon calcitoninwhere an oligomer is coupled to the amino functionalities of Lys¹¹ andthe Lys¹⁸.

Mixtures of calcitonin drug-oligomer conjugates where each conjugate inthe mixture has the same number of polyethylene glycol subunits may besynthesized by various methods. For example, a mixture of oligomersconsisting of carboxylic acid and polyethylene glycol where eacholigomer in the mixture has the same number of polyethylene glycolsubunits is synthesized by contacting a mixture of carboxylic acid witha mixture of polyethylene glycol where each polyethylene glycol moleculein the mixture has the same number of polyethylene glycol subunits underconditions sufficient to provide a mixture of oligomers where eacholigomer in the mixture has the same number of polyethylene glycolsubunits. The oligomers of the mixture where each oligomer in themixture has the same number of polyethylene glycol subunits are thenactivated so that they are capable of reacting with a calcitonin drug toprovide a calcitonin drug-oligomer conjugate. One embodiment of asynthesis route for providing a mixture of activated oligomers whereeach oligomer in the mixture has the same number of polyethylene glycolsubunits is illustrated in FIG. 3 and described in Examples 11–18hereinbelow. Another embodiment of a synthesis route for providing amixture of activated oligomers where each oligomer in the mixture hasthe same number of polyethylene glycol subunits is illustrated in FIG. 4and described in Examples 19–24 hereinbelow. Still another embodiment ofa synthesis route for providing a mixture of activated oligomers whereeach oligomer in the mixture has the same number of polyethylene glycolsubunits is illustrated in FIG. 5 and described in Examples 25–29hereinbelow. Yet another embodiment of a synthesis route for providing amixture of activated oligomers where each oligomer in the mixture hasthe same number of polyethylene glycol subunits is illustrated in FIG. 6and described in Examples 30–31 hereinbelow. Another embodiment of asynthesis route for providing a mixture of activated oligomers whereeach oligomer in the mixture has the same number of polyethylene glycolsubunits is illustrated in FIG. 7 and described in Examples 32–37hereinbelow. Still another embodiment of a synthesis route for providinga mixture of activated oligomers where each oligomer in the mixture hasthe same number of polyethylene glycol subunits is illustrated in FIG. 8and described in Example 38 hereinbelow. Yet another embodiment of asynthesis route for providing a mixture of activated oligomers whereeach oligomer in the mixture has the same number of polyethylene glycolsubunits is illustrated in FIG. 9 and described in Example 39hereinbelow. Another embodiment of a synthesis route for providing amixture of activated oligomers having a mixture of activated oligomerswhere each oligomer in the mixture has the same number of polyethyleneglycol subunits is illustrated in FIG. 10 and described in Example 40hereinbelow.

The mixture of activated oligomers where each oligomer in the mixturehas the same number of polyethylene glycol subunits is reacted with amixture of calcitonin drugs under conditions sufficient to provide amixture of calcitonin drug-oligomer conjugates. A preferred synthesis isdescribed in Example 41 hereinbelow. As will be understood by thoseskilled in the art, the reaction conditions (e.g., selected molarratios, solvent mixtures and/or pH) may be controlled such that themixture of calcitonin drug-oligomer conjugates resulting from thereaction of the mixture of activated oligomers where each oligomer inthe mixture has the same number of polyethylene glycol subunits and themixture of calcitonin drugs is a mixture of conjugates where eachconjugate in the mixture has the same number of polyethylene glycolsubunits. For example, conjugation at the amino functionality of lysinemay be suppressed by maintaining the pH of the reaction solution belowthe pK_(a) of lysine. Alternatively, the mixture of calcitonindrug-oligomer conjugates may be separated and isolated utilizing, forexample, HPLC to provide a mixture of calcitonin drug-oligomerconjugates, for example mono-, di-, or tri-conjugates, where eachconjugate in the mixture has the same number of polyethylene glycolsubunits. The degree of conjugation (e.g., whether the isolated moleculeis a mono-, di-, or tri-conjugate) of a particular isolated conjugatemay be determined and/or verified utilizing various techniques as willbe understood by those skilled in the art including, but not limited to,mass spectroscopy. The particular conjugate structure (e.g., whether theoligomer is at Lys¹¹, Lys¹⁸ or the N-terminus of a salmon calcitoninmonoconjugate) may be determined and/or verified utilizing varioustechniques as will be understood by those skilled in the art including,but not limited to, sequence analysis, peptide mapping, selectiveenzymatic cleavage, and/or endopeptidase cleavage.

As will be understood by those skilled in the art, one or more of thereaction sites on the calcitonin drug may be blocked by, for example,reacting the calcitonin drug with a suitable blocking reagent such asN-tert-butoxycarbonyl (t-BOC), or N-(9-fluorenylmethoxycarbonyl)(N-FMOC). This process may be preferred, for example, when thecalcitonin drug is a polypeptide and it is desired to form anunsaturated conjugate (i.e., a conjugate wherein not all nucleophilicresidues are conjugated) having an oligomer at the N-terminus of thepolypeptide. Following such blocking, the mixture of blocked calcitonindrugs may be reacted with the mixture of activated oligomers where eacholigomer in the mixture has the same number of polyethylene glycolsubunits to provide a mixture of calcitonin drug-oligomer conjugateshaving oligomer(s) coupled to one or more nucleophilic residues andhaving blocking moieties coupled to other nucleophilic residues. Afterthe conjugation reaction, the calcitonin drug-oligomer conjugates may bede-blocked as will be understood by those skilled in the art. Ifnecessary, the mixture of calcitonin drug-oligomer conjugates may thenbe separated as described above to provide a mixture of calcitonindrug-oligomer conjugates where each conjugate in the mixture has thesame number of polyethylene glycol subunits. Alternatively, the mixtureof calcitonin drug-oligomer conjugates may be separated prior tode-blocking.

Mixtures of calcitonin drug-oligomer conjugates where each conjugate inthe mixture has the same number of polyethylene glycol subunitsaccording to embodiments of the present invention preferably haveimproved properties when compared with those of conventional mixtures.For example, a mixture of calcitonin drug-oligomer conjugates where eachconjugate in the mixture has the same number of polyethylene glycolsubunits preferably is capable of lowering serum calcium levels by atleast 5 percent. Preferably, the mixture of conjugates is capable oflowering serum calcium levels by at least 10, 11, 12, 13 or 14 percent.More preferably, the mixture of conjugates is capable of lowering serumcalcium levels by at least 15, 16, 17, 18 or 19 percent, and, mostpreferably, the mixture of conjugates is capable of lowering serumcalcium levels by at least 20 percent.

As anther example, a mixture of calcitonin drug-oligomer conjugateswhere each conjugate in the mixture has the same number of polyethyleneglycol subunits preferably has an increased resistance to degradation bychymotrypsin and/or trypsin when compared to the resistance todegradation by chymotrypsin and/or trypsin, respectively, of thecalcitonin drug which is not coupled to the oligomer. Resistance tochymotrypsin or trypsin corresponds to the percent remaining when themolecule to be tested is digested in the applicable enzyme using aprocedure similar to the one outlined in Example 51 below. Preferably,the resistance to degradation by chymotrypsin of the mixture ofcalcitonin drug-oligomer conjugates is about 10 percent greater than theresistance to degradation by chymotrypsin of the mixture of calcitonindrugs that is not conjugated with the oligomer. More preferably, theresistance to degradation by chymotrypsin of the mixture of calcitonindrug-oligomer conjugates is about 15 percent greater than the resistanceto degradation by chymotrypsin of the mixture of calcitonin drug that isnot conjugated with the oligomer, and, most preferably, the resistanceto degradation by chymotrypsin of the mixture of calcitonindrug-oligomer conjugates is about 20 percent greater than the resistanceto degradation by chymotrypsin of the mixture of calcitonin drug that isnot conjugated with the oligomer. Preferably, the resistance todegradation by trypsin of the mixture of calcitonin drug-oligomerconjugates is about 10 percent greater than the resistance todegradation by trypsin of the mixture of calcitonin drug that is notconjugated with the oligomer. More preferably, the resistance todegradation by trypsin of the mixture of calcitonin drug-oligomerconjugates is about 20 percent greater than the resistance todegradation by trypsin of the mixture of calcitonin drug that is notconjugated with the oligomer, and, most preferably, the resistance todegradation by trypsin of the mixture of calcitonin drug-oligomerconjugates is about 30 percent greater than the resistance todegradation by trypsin of the mixture of calcitonin drug that is notconjugated with the oligomer.

As still another example, a mixture of calcitonin drug-oligomerconjugates where each conjugate in the mixture has the same number ofpolyethylene glycol subunits preferably has a higher bioefficacy thanthe bioefficacy of the calcitonin drug which is not coupled to theoligomer. The bioefficacy of a particular compound corresponds to itsarea-under-the-curve (AUC) value. Preferably, the bioefficacy of themixture is about 5 percent greater than the bioefficacy of thecalcitonin drug which is not coupled to the oligomer. More preferably,the bioefficacy of the mixture is about 10 percent greater than thebioefficacy of the calcitonin drug which is not coupled to the oligomer.

As yet another example, a mixture of calcitonin drug-oligomer conjugateswhere each conjugate in the mixture has the same number of polyethyleneglycol subunits preferably has an in vivo activity that is greater thanthe in vivo activity of a polydispersed mixture of calcitonindrug-oligomer conjugates having the same number average molecular weightas the mixture of calcitonin drug-oligomer conjugates where eachconjugate in the mixture has the same number of polyethylene glycolsubunits. As will be understood by those skilled in the art, the numberaverage molecular weight of a mixture may be measured by various methodsincluding, but not limited to, size exclusion chromatography such as gelpermeation chromatography as described, for example, in H. R. Allcock &F. W. Lampe, CONTEMPORARY POLYMER CHEMISTRY 394–402 (2d. ed., 1991).

As another example, a mixture of calcitonin drug-oligomer conjugateswhere each conjugate in the mixture has the same number of polyethyleneglycol subunits preferably has an in vitro activity that is greater thanthe in vitro activity of a polydispersed mixture of calcitonindrug-oligomer conjugates having the same number average molecular weightas the mixture of calcitonin drug-oligomer conjugates where eachconjugate in the mixture has the same number of polyethylene glycolsubunits. As will be understood by those skilled in the art, the numberaverage molecular weight of a mixture may be measured by various methodsincluding, but not limited to, size exclusion chromatography.

As still another example, a mixture of calcitonin drug-oligomerconjugates where each conjugate in the mixture has the same number ofpolyethylene glycol subunits preferably has an increased resistance todegradation by chymotrypsin and/or trypsin when compared to theresistance to degradation by chymotrypsin and/or trypsin of apolydispersed mixture of calcitonin drug-oligomer conjugates having thesame number average molecular weight as the mixture of calcitonindrug-oligomer conjugates where each conjugate in the mixture has thesame number of polyethylene glycol subunits. As will be understood bythose skilled in the art, the number average molecular weight of amixture may be measured by various methods including, but not limitedto, size exclusion chromatography.

As yet another example, a mixture of calcitonin drug-oligomer conjugateswhere each conjugate in the mixture has the same number of polyethyleneglycol subunits preferably has an inter-subject variability that is lessthan the inter-subject variability of a polydispersed mixture ofcalcitonin drug-oligomer conjugates having the same number averagemolecular weight as the mixture of calcitonin drug-oligomer conjugateswhere each conjugate in the mixture has the same number of polyethyleneglycol subunits. As will be understood by those skilled in the art, thenumber average molecular weight of a mixture may be measured by variousmethods including, but not limited to, size exclusion chromatography.The inter-subject variability may be measured by various methods, aswill be understood by those skilled in the art. The inter-subjectvariability is preferably calculated as follows. The area under a doseresponse curve (AUC) (i.e., the area between the dose-response curve anda baseline value) is determined for each subject. The average AUC forall subjects is determined by summing the AUCs of each subject anddividing the sum by the number of subjects. The absolute value of thedifference between the subject's AUC and the average AUC is thendetermined for each subject. The absolute values of the differencesobtained are then summed to give a value that represents theinter-subject variability. Lower values represent lower inter-subjectvariabilities and higher values represent higher inter-subjectvariabilities.

Mixtures of calcitonin drug-oligomer conjugates where each conjugate inthe mixture has the same number of polyethylene glycol subunitsaccording to embodiments of the present invention preferably have two ormore of the above-described improved properties. More preferably,mixtures of calcitonin drug-oligomer conjugates where each conjugate inthe mixture has the same number of polyethylene glycol subunitsaccording to embodiments of the present invention have three or more ofthe above-described improved properties. Most preferably, mixtures ofcalcitonin drug-oligomer conjugates where each conjugate in the mixturehas the same number of polyethylene glycol subunits according toembodiments of the present invention have four or more of theabove-described improved properties.

According to still other embodiments of the present invention, a mixtureof conjugates is provided in which each conjugate has the same molecularweight and has the structure of Formula A:

wherein:

-   B is a bonding moiety;-   L is a linker moiety;-   G, G′ and G″ are individually selected spacer moieties;-   R is a lipophilic moiety and R′ is a polyalkylene glycol moiety, or    R′ is the lipophilic moiety and R is the polyalkylene glycol moiety;-   T is a terminating moiety;-   j, k, m and n are individually 0 or 1; and-   p is an integer from 1 to the number of nucleophilic residues on the    calcitonin drug.

The calcitonin drug is preferably calcitonin. More preferably, thecalcitonin drug is salmon calcitonin. However, it is to be understoodthat the calcitonin drug may be selected from various calcitonin drugsknown to those skilled in the art including, for example, calcitoninprecursor peptides, calcitonin, calcitonin analogs, calcitoninfragments, and calcitonin fragment analogs. Calcitonin precursorpeptides include, but are not limited to, katacalcin (PDN-21)(C-procalcitonin), and N-proCT (amino-terminal procalcitonin cleavagepeptide), human. Calcitonin analogs may be provided by substitution ofone or more amino acids in calcitonin as described above. Calcitoninfragments include, but are not limited to, calcitonin 1–7, human; andcalcitonin 8–32, salmon. Calcitonin fragment analogs may be provided bysubstitution of one or more of the amino acids in a calcitonin fragmentas described above.

According to these embodiments of the present invention, thepolyalkylene glycol moiety of the oligomer preferably has at least 2, 3or 4 polyalkylene glycol subunits. More preferably, the polyalkyleneglycol moiety has at least 5 or 6 polyalkylene glycol subunits and, mostpreferably, the polyethylene glycol moiety has at least 7 polyalkyleneglycol subunits. The polyalkylene glycol moiety is preferably a lowerpolyalkylene glycol moiety such as a polyethylene glycol moiety, apolypropylene glycol moiety, or a polybutylene glycol moiety. Morepreferably, the polyalkylene glycol moiety is a polyethylene glycolmoiety or a polypropylene glycol moiety. Most preferably, thepolyalkylene glycol moiety is a polyethylene glycol moiety. When thepolyalkylene glycol moiety is a polypropylene glycol moiety, the moietypreferably has a uniform (i.e., not random) structure. An exemplarypolypropylene glycol moiety having a uniform structure is as follows:

This uniform polypropylene glycol structure may be described as havingonly one methyl substituted carbon atom adjacent each oxygen atom in thepolypropylene glycol chain. Such uniform polypropylene glycol moietiesmay exhibit both lipophilic and hydrophilic characteristics and thus beuseful in providing amphiphilic calcitonin drug-oligomer conjugateswithout the use of lipophilic polymer moieties. Furthermore, couplingthe secondary alcohol moiety of the polypropylene glycol moiety with acalcitonin drug may provide the calcitonin drug (e.g., salmoncalcitonin) with improved resistance to degradation caused by enzymessuch as trypsin and chymotrypsin found, for example, in the gut.

Uniform polypropylene glycol according to embodiments of the presentinvention is preferably synthesized as illustrated in FIGS. 11 through13, which will now be described. As illustrated in FIG. 11,1,2-propanediol 53 is reacted with a primary alcohol blocking reagent toprovide a secondary alcohol extension monomer 54. The primary alcoholblocking reagent may be various primary alcohol blocking reagents aswill be understood by those skilled in the art including, but notlimited to, silylchloride compounds such as t-butyldiphenylsilylchlorideand t-butyldimethylsilylchloride, and esterification reagents such asAc₂O. Preferably, the primary alcohol blocking reagent is a primaryalcohol blocking reagent that is substantially non-reactive withsecondary alcohols, such as t-butyldiphenylsilylchloride ort-butyldimethylsilylchloride. The secondary alcohol extension monomer(54) may be reacted with methanesulfonyl chloride (MeSO₂Cl) to provide aprimary extension alcohol monomer mesylate 55.

Alternatively, the secondary alcohol extension monomer 54 may be reactedwith a secondary alcohol blocking reagent to provide compound 56. Thesecondary alcohol blocking reagent may be various secondary alcoholblocking reagents as will be understood by those skilled in the artincluding, but not limited to, benzyl chloride. The compound 56 may bereacted with a B₁ de-blocking reagent to remove the blocking moiety B₁and provide a primary alcohol extension monomer 57. The B₁ de-blockingreagent may be selected from various de-blocking reagents as will beunderstood by one skilled in the art. When the primary alcohol has beenblocked by forming an ester, the B₁ de-blocking reagent is ade-esterification reagent, such as a base (e.g., potassium carbonate).When the primary alcohol has been blocked using a silylchloride, the B₁de-blocking reagent is preferably tetrabutylammonium fluoride (TBAF).The primary alcohol extension monomer 57 may be reacted with methanesulfonyl chloride to provide a secondary alcohol extension monomermesylate 58.

The primary alcohol extension monomer 54 and the secondary alcoholextension monomer 57 may be capped as follows. The secondary alcoholextension monomer 54 may be reacted with a capping reagent to provide acompound 59. The capping reagent may be various capping reagents as willbe understood by those skilled in the art including, but not limited to,alkyl halides such as methyl chloride. The compound 59 may be reactedwith a B₁ de-blocking agent as described above to provide a primaryalcohol capping monomer 60. The primary alcohol capping monomer 60 maybe reacted with methane sulfonyl chloride to provide the secondaryalcohol capping monomer mesylate 61. The primary alcohol extensionmonomer 57 may be reacted with a capping reagent to provide a compound62. The capping reagent may be various capping reagents as describedabove. The compound 62 may be reacted with a B₂ de-blocking reagent toremove the blocking moiety B₂ and provide a secondary alcohol cappingmonomer 63. The B₂ de-blocking reagent may be various de-blocking agentsas will be understood by those skilled in the art including, but notlimited to, H₂ in the presence of a palladium/activated carbon catalyst.The secondary alcohol capping monomer may be reacted withmethanesulfonyl chloride to provide a primary alcohol capping monomermesylate 64. While the embodiments illustrated in FIG. 11 show thesynthesis of capping monomers, it is to be understood that similarreactions may be performed to provide capping polymers.

In general, chain extensions may be effected by reacting a primaryalcohol extension mono- or poly-mer such as the primary alcoholextension monomer 57 with a primary alcohol extension mono- or poly-mermesylate such as the primary alcohol extension monomer mesylate 55 toprovide various uniform polypropylene chains or by reacting a secondaryalcohol extension mono- or poly-mer such as the secondary alcoholextension monomer 54 with a secondary alcohol extension mono-or poly-mermesylate such as the secondary alcohol extension monomer mesylate 58.

For example, in FIG. 13, the primary alcohol extension monomer mesylate55 is reacted with the primary alcohol extension monomer 57 to provide adimer compound 65. Alternatively, the secondary alcohol extensionmonomer mesylate 58 may be reacted with the secondary alcohol extensionmonomer 54 to provide the dimer compound 65. The B₁ blocking moiety onthe dimer compound 65 may be removed using a B₁ de-blocking reagent asdescribed above to provide a primary alcohol extension dimer 66. Theprimary alcohol extension dimer 66 may be reacted with methane sulfonylchloride to provide a secondary alcohol extension dimer mesylate 67.Alternatively, the B₂ blocking moiety on the dimer compound 65 may beremoved using the B₂ de-blocking reagent as described above to provide asecondary alcohol extension dimer 69. The secondary alcohol extensiondimer 69 may be reacted with methane sulfonyl chloride to provide aprimary alcohol extension dimer mesylate 70.

As will be understood by those skilled in the art, the chain extensionprocess may be repeated to achieve various other chain lengths. Forexample, as illustrated in FIG. 13, the primary alcohol extension dimer66 may be reacted with the primary alcohol extension dimer mesylate 70to provide a tetramer compound 72. As further illustrated in FIG. 13, ageneric chain extension reaction scheme involves reacting the primaryalcohol extension mono- or poly-mer 73 with the primary alcoholextension mono- or poly-mer mesylate 74 to provide the uniformpolypropylene polymer 75. The values of m and n may each range from 0 to1000 or more. Preferably, m and n are each from 0 to 50. While theembodiments illustrated in FIG. 13 show primary alcohol extension mono-and/or poly-mers being reacted with primary alcohol extension mono-and/or poly-mer mesylates, it is to be understood that similar reactionsmay be carried out using secondary alcohol extension mono- and/orpoly-mers and secondary alcohol extension mono- and/or poly-mermesylates.

An end of a primary alcohol extension mono- or poly-mer or an end of aprimary alcohol extension mono- or poly-mer mesylate may be reacted witha primary alcohol capping mono- or poly-mer mesylate or a primaryalcohol capping mono- or poly-mer, respectively, to provide a cappeduniform polypropylene chain. For example, as illustrated in FIG. 12, theprimary alcohol extension dimer mesylate 70 is reacted with the primaryalcohol capping monomer 60 to provide the capped/blocked primary alcoholextension trimer 71. As will be understood by those skilled in the art,the B₁ blocking moiety may be removed and the resulting capped primaryalcohol extension trimer may be reacted with a primary alcohol extensionmono- or poly-mer mesylate to extend the chain of the capped trimer 71.

An end of a secondary alcohol extension mono-or poly-mer or an end of asecondary alcohol extension mono-or poly-mer mesylate may be reactedwith a secondary alcohol capping mono-or poly-mer mesylate or asecondary alcohol capping mono- or poly-mer, respectively, to provide acapped uniform polypropylene chain. For example, as illustrated in FIG.12, the secondary alcohol extension dimer mesylate 67 is reacted withthe secondary alcohol capping monomer 63 to provide the capped/blockedprimary alcohol extension trimer 68. The B₂ blocking moiety may beremoved as described above and the resulting capped secondary alcoholextension trimer may be reacted with a secondary alcohol extension mermesylate to extend the chain of the capped trimer 68. While thesyntheses illustrated in FIG. 12 show the reaction of a dimer with acapping monomer to provide a trimer, it is to be understood that thecapping process may be performed at any point in the synthesis of auniform polypropylene glycol moiety, or, alternatively, uniformpolypropylene glycol moieties may be provided that are not capped. Whilethe embodiments illustrated in FIG. 12 show the capping of apolybutylene oligomer by synthesis with a capping monomer, it is to beunderstood that polybutylene oligomers of the present invention may becapped directly (i.e., without the addition of a capping monomer) usinga capping reagent as described above in FIG. 11.

Uniform polypropylene glycol moieties according to embodiments of thepresent invention may be coupled to a calcitonin drug, a lipophilicmoiety such as a carboxylic acid, and/or various other moieties byvarious methods as will be understood by those skilled in the artincluding, but not limited to, those described herein with respect topolyethylene glycol moieties.

According to these embodiments of the present invention, the lipophilicmoiety is a lipophilic moiety as will be understood by those skilled inthe art. The lipophilic moiety is preferably a saturated or unsaturated,linear or branched alkyl moiety or a saturated or unsaturated, linear orbranched fatty acid moiety. When the lipophilic moiety is an alkylmoiety, it is preferably a linear, saturated or unsaturated alkyl moietyhaving 1 to 28 carbon atoms. More preferably, the alkyl moiety has 2 to12 carbon atoms. When the lipophilic moiety is a fatty acid moiety, itis preferably a natural fatty acid moiety that is linear, saturated orunsaturated, having 2 to 18 carbon atoms. More preferably, the fattyacid moiety has 3 to 14 carbon atoms. Most preferably, the fatty acidmoiety has at least 4, 5 or 6 carbon atoms.

According to these embodiments of the present invention, the spacermoieties, G, G′ and G″, are spacer moieties as will be understood bythose skilled in the art. Spacer moieties are preferably selected fromthe group consisting of sugar, cholesterol and glycerine moieties.Preferably, oligomers of these embodiments do not include spacermoieties (i.e., k, m and n are preferably 0).

According to these embodiments of the present invention, the linkermoiety, L, may be used to couple the oligomer with the drug as will beunderstood by those skilled in the art. Linker moieties are preferablyselected from the group consisting of alkyl and fatty acid moieties.

According to these embodiments of the present invention, the terminatingmoiety is preferably an alkyl or alkoxy moiety, and is more preferably alower alkyl or lower alkoxy moiety. Most preferably, the terminatingmoiety is methyl or methoxy. While the terminating moiety is preferablyan alkyl or alkoxy moiety, it is to be understood that the terminatingmoiety may be various moieties as will be understood by those skilled inthe art including, but not limited to, sugars, cholesterol, alcohols,and fatty acids.

According to these embodiments of the present invention, the oligomer,which is represented by the bracketed portion of the structure ofFormula A, is covalently coupled to the calcitonin drug. In someembodiments, the calcitonin drug is coupled to the oligomer utilizing ahydrolyzable bond (e.g., an ester or carbonate bond). A hydrolyzablecoupling may provide a calcitonin drug-oligomer conjugate that acts as aprodrug. In certain instances, for example where the calcitonindrug-oligomer conjugate is inactive (i.e., the conjugate lacks theability to affect the body through the calcitonin drug's primarymechanism of action), a hydrolyzable coupling may provide for atime-release or controlled-release effect, administering the calcitonindrug over a given time period as one or more oligomers are cleaved fromtheir respective calcitonin drug-oligomer conjugates to provide theactive drug. In other embodiments, the calcitonin drug is coupled to theoligomer utilizing a non-hydrolyzable bond (e.g., a carbamate, amide, orether bond). Use of a non-hydrolyzable bond may be preferable when it isdesirable to allow the calcitonin drug-oligomer conjugate to circulatein the bloodstream for an extended period of time, preferably at least 2hours. The bonding moiety, B, may be various bonding moieties that maybe used to covalently couple the oligomer with the calcitonin drug aswill be understood by those skilled in the art. Bonding moieties arepreferably selected from the group consisting of covalent bond(s), estermoieties, carbonate moieties, carbamate moieties, amide moieties andsecondary amine moieties.

The variable p is an integer from 1 to the number of nucleophilicresidues on the calcitonin drug. When p is greater than 1, more than oneoligomer (i.e., a plurality of oligomers) is coupled to the drug.According the these embodiments of the present invention, the oligomersin the plurality are the same. When a plurality of oligomers are coupledto the drug, it may be preferable to couple one or more of the oligomersto the drug with hydrolyzable bonds and couple one or more of theoligomers to the drug with non-hydrolyzable bonds. Alternatively, all ofthe bonds coupling the plurality of oligomers to the drug may behydrolyzable, but have varying degrees of hydrolyzability such that, forexample, one or more of the oligomers is rapidly removed from the drugby hydrolysis in the body and one or more of the oligomers is slowlyremoved from the drug by hydrolysis in the body. When the calcitonindrug is salmon calcitonin, p is preferably 1 or 2, and is morepreferably 2.

The oligomer may be coupled to the calcitonin drug at variousnucleophilic residues of the calcitonin drug including, but not limitedto, nucleophilic hydroxyl functions and/or amino functions. When thecalcitonin drug is a polypeptide, a nucleophilic hydroxyl function maybe found, for example, at serine and/or tyrosine residues, and anucleophilic amino function may be found, for example, at histidineand/or lysine residues, and/or at the one or more N-termini of thepolypeptide. When an oligomer is coupled to the one or more N-terminusof the calcitonin polypeptide, the coupling preferably forms a secondaryamine. When the calcitonin drug is salmon calcitonin, for example, theoligomer may be coupled to an amino functionality of the salmoncalcitonin, including the amino functionality of Lys¹¹, Lys¹⁸ and/or theN-terminus. While one or more oligomers may be coupled to the salmoncalcitonin, a higher bioefficacy, such as improved serum calciumlowering ability, is observed for the di-conjugated salmon calcitoninwhere an oligomer is coupled to the amino functionalities of Lys¹¹ andthe Lys¹⁸.

Mixtures of calcitonin drug-oligomer conjugates where each conjugate inthe mixture has the same molecular weight and has the structure ofFormula A may be synthesized by various methods. For example, a mixtureof oligomers consisting of carboxylic acid and polyethylene glycol issynthesized by contacting a mixture of carboxylic acid with a mixture ofpolyethylene glycol under conditions sufficient to provide a mixture ofoligomers. The oligomers of the mixture are then activated so that theyare capable of reacting with a calcitonin drug to provide a calcitonindrug-oligomer conjugate. One embodiment of a synthesis route forproviding a mixture of activated oligomers where each oligomer has thesame molecular weight and has a structure of the oligomer of Formula Ais illustrated in FIG. 3 and described in Examples 11–18 hereinbelow.Another embodiment of a synthesis route for providing a mixture ofactivated oligomers where each oligomer has the same molecular weightand has a structure of the oligomer of Formula A is illustrated in FIG.4 and described in Examples 19–24 hereinbelow. Still another embodimentof a synthesis route for providing a mixture of activated oligomerswhere each oligomer has the same molecular weight and has a structure ofthe oligomer of Formula A is illustrated in FIG. 5 and described inExamples 25–29 hereinbelow. Yet another embodiment of a synthesis routefor providing a mixture of activated oligomers where each oligomer hasthe same molecular weight and has a structure of the oligomer of FormulaA is illustrated in FIG. 6 and described in Examples 30–31 hereinbelow.Another embodiment of a synthesis route for providing a mixture ofactivated oligomers where each oligomer has the same molecular weightand has a structure of the oligomer of Formula A is illustrated in FIG.7 and described in Examples 32–37 hereinbelow. Still another embodimentof a synthesis route for providing a mixture of activated oligomerswhere each oligomer has the same molecular weight and has a structure ofthe oligomer of Formula A is illustrated in FIG. 8 and described inExample 38 hereinbelow. Yet another embodiment of a synthesis route forproviding a mixture of activated oligomers where each oligomer has thesame molecular weight and has a structure of the oligomer of Formula Ais illustrated in FIG. 9 and described in Example 39 hereinbelow.Another embodiment of a synthesis route for providing a mixture ofactivated oligomers where each oligomer has the same molecular weightand has a structure of the oligomer of Formula A is illustrated in FIG.10 and described in Example 40 hereinbelow.

The mixture of activated oligomers where each oligomer has the samemolecular weight and has a structure of the oligomer of Formula A isreacted with a mixture of calcitonin drugs where each drug in themixture has the same molecular weight under conditions sufficient toprovide a mixture of calcitonin drug-oligomer conjugates. A preferredsynthesis is described in Example 41 hereinbelow. As will be understoodby those skilled in the art, the reaction conditions (e.g., selectedmolar ratios, solvent mixtures and/or pH) may be controlled such thatthe mixture of calcitonin drug-oligomer conjugates resulting from thereaction of the mixture of activated oligomers where each oligomer hasthe same molecular weight and has a structure of the oligomer of FormulaA and the mixture of calcitonin drugs is a mixture of conjugates whereeach conjugate has the same molecular weight and has the structureFormula A. For example, conjugation at the amino functionality of lysinemay be suppressed by maintaining the pH of the reaction solution belowthe pK_(a) of lysine. Alternatively, the mixture of calcitonindrug-oligomer conjugates may be separated and isolated utilizing, forexample, HPLC to provide a mixture of calcitonin drug-oligomerconjugates, for example mono-, di-, or tri-conjugates, where eachconjugate in the mixture has the same number molecular weight and hasthe structure of Formula A. The degree of conjugation (e.g., whether theisolated molecule is a mono-, di-, or tri-conjugate) of a particularisolated conjugate may be determined and/or verified utilizing varioustechniques as will be understood by those skilled in the art including,but not limited to, mass spectroscopy. The particular conjugatestructure (e.g., whether the oligomer is at Lys¹¹, Lys¹⁸ or theN-terminus of a salmon calcitonin monoconjugate) may be determinedand/or verified utilizing various techniques as will be understood bythose skilled in the art including, but not limited to, sequenceanalysis, peptide mapping, selective enzymatic cleavage, and/orendopeptidase cleavage.

As will be understood by those skilled in the art, one or more of thereaction sites on the calcitonin drug may be blocked by, for example,reacting the calcitonin drug with a suitable blocking reagent such asN-tert-butoxycarbonyl (t-BOC), or N-(9-fluorenylmethoxycarbonyl)(N-FMOC). This process may be preferred, for example, when thecalcitonin drug is a polypeptide and it is desired to form anunsaturated conjugate (i.e., a conjugate wherein not all nucleophilicresidues are conjugated) having an oligomer at the N-terminus of thepolypeptide. Following such blocking, the mixture of blocked calcitonindrugs may be reacted with the mixture of activated oligomers where eacholigomer in the mixture has the same molecular weight and has astructure of the oligomer of Formula A to provide a mixture ofcalcitonin drug-oligomer conjugates having oligomer(s) coupled to one ormore nucleophilic residues and having blocking moieties coupled to othernucleophilic residues. After the conjugation reaction, the calcitonindrug-oligomer conjugates may be de-blocked as will be understood bythose skilled in the art. If necessary, the mixture of calcitonindrug-oligomer conjugates may then be separated as described above toprovide a mixture of calcitonin drug-oligomer conjugates where eachconjugate in the mixture has the same number molecular weight and hasthe structure of Formula A. Alternatively, the mixture of calcitonindrug-oligomer conjugates may be separated prior to de-blocking.

Mixtures of calcitonin drug-oligomer conjugates where each conjugate inthe mixture has the same molecular weight and has the structure ofFormula A according to embodiments of the present invention preferablyhave improved properties when compared with those of conventionalmixtures. For example, a mixture of calcitonin drug-oligomer conjugateswhere each conjugate in the mixture has the same molecular weight andhas the structure of Formula A preferably is capable of lowering serumcalcium levels by at least 5 percent. Preferably, the mixture ofconjugates is capable of lowering serum calcium levels by at least 10,11, 12, 13 or 14 percent. More preferably, the mixture of conjugates iscapable of lowering serum calcium levels by at least 15, 16, 17, 18 or19 percent, and, most preferably, the mixture of conjugates is capableof lowering serum calcium levels by at least 20 percent.

As another example, a mixture of calcitonin drug-oligomer conjugateswhere each conjugate in the mixture has the same molecular weight andhas the structure of Formula A preferably has an increased resistance todegradation by chymotrypsin and/or trypsin when compared to theresistance to degradation by chymotrypsin and/or trypsin, respectively,of the calcitonin drug which is not coupled to the oligomer. Resistanceto chymotrypsin or trypsin corresponds to the percent remaining when themolecule to be tested is digested in the applicable enzyme using aprocedure similar to the one outlined in Example 51 below. Preferably,the resistance to degradation by chymotrypsin of the mixture ofcalcitonin drug-oligomer conjugates is about 10 percent greater than theresistance to degradation by chymotrypsin of the mixture of calcitonindrugs that is not conjugated with the oligomer. More preferably, theresistance to degradation by chymotrypsin of the mixture of calcitonindrug-oligomer conjugates is about 15 percent greater than the resistanceto degradation by chymotrypsin of the mixture of calcitonin drug that isnot conjugated with the oligomer, and, most preferably, the resistanceto degradation by chymotrypsin of the mixture of calcitonindrug-oligomer conjugates is about 20 percent greater than the resistanceto degradation by chymotrypsin of the mixture of calcitonin drug that isnot conjugated with the oligomer. Preferably, the resistance todegradation by trypsin of the mixture of calcitonin drug-oligomerconjugates is about 10 percent greater than the resistance todegradation by trypsin of the mixture of calcitonin drug that is notconjugated with the oligomer. More preferably, the resistance todegradation by trypsin of the mixture of calcitonin drug-oligomerconjugates is about 20 percent greater than the resistance todegradation by trypsin of the mixture of calcitonin drug that is notconjugated with the oligomer, and, most preferably, the resistance todegradation by trypsin of the mixture of calcitonin drug-oligomerconjugates is about 30 percent greater than the resistance todegradation by trypsin of the mixture of calcitonin drug that is notconjugated with the oligomer.

As still another example, a mixture of calcitonin drug-oligomerconjugates where each conjugate in the mixture has the same molecularweight and has the structure of Formula A preferably has a higherbioefficacy than the bioefficacy of the calcitonin drug which is notcoupled to the oligomer. The bioefficacy of a particular compoundcorresponds to its area-under-the-curve (AUC) value. Preferably, thebioefficacy of the mixture is about 5 percent greater than thebioefficacy of the calcitonin drug which is not coupled to the oligomer.More preferably, the bioefficacy of the mixture is about 10 percentgreater than the bioefficacy of the calcitonin drug which is not coupledto the oligomer.

As yet another example, a mixture of calcitonin drug-oligomer conjugateswhere each conjugate in the mixture has the same molecular weight andhas the structure of Formula A preferably has an in vivo activity thatis greater than the in vivo activity of a polydispersed mixture ofcalcitonin drug-oligomer conjugates having the same number averagemolecular weight as the mixture of calcitonin drug-oligomer conjugateswhere each conjugate in the mixture has the same molecular weight andhas the structure of Formula A. As will be understood by those skilledin the art, the number average molecular weight of a mixture may bemeasured by various methods including, but not limited to, sizeexclusion chromatography such as gel permeation chromatography asdescribed, for example, in H. R. Allcock & F. W. Lampe, CONTEMPORARYPOLYMER CHEMISTRY 394–402 (2d. ed., 1991).

As another example, a mixture of calcitonin drug-oligomer conjugateswhere each conjugate in the mixture has the same molecular weight andhas the structure of Formula A preferably has an in vitro activity thatis greater than the in vitro activity of a polydispersed mixture ofcalcitonin drug-oligomer conjugates having the same number averagemolecular weight as the mixture of calcitonin drug-oligomer conjugateswhere each conjugate in the mixture has the same molecular weight andhas the structure of Formula A. As will be understood by those skilledin the art, the number average molecular weight of a mixture may bemeasured by various methods including, but not limited to, sizeexclusion chromatography.

As still another example, a mixture of calcitonin drug-oligomerconjugates where each conjugate in the mixture has the same molecularweight and has the structure of Formula A preferably has an increasedresistance to degradation by chymotrypsin and/or trypsin when comparedto the resistance to degradation by chymotrypsin and/or trypsin of apolydispersed mixture of calcitonin drug-oligomer conjugates having thesame number average molecular weight as the mixture of calcitonindrug-oligomer conjugates where each conjugate in the mixture has thesame molecular weight and has the structure of Formula A. As will beunderstood by those skilled in the art, the number average molecularweight of a mixture may be measured by various methods including, butnot limited to, size exclusion chromatography.

As yet another example, a mixture of calcitonin drug-oligomer conjugateswhere each conjugate in the mixture has the same molecular weight andhas the structure of Formula A preferably has an inter-subjectvariability that is less than the inter-subject variability of apolydispersed mixture of calcitonin drug-oligomer conjugates having thesame number average molecular weight as the mixture of calcitonindrug-oligomer conjugates where each conjugate in the mixture has thesame molecular weight and has the structure of Formula A. As will beunderstood by those skilled in the art, the number average molecularweight of a mixture may be measured by various methods including, butnot limited to, size exclusion chromatography. The inter-subjectvariability may be measured by various methods, as will be understood bythose skilled in the art. The inter-subject variability is preferablycalculated as follows. The area under a dose response curve (AUC) (i.e.,the area between the dose-response curve and a baseline value) isdetermined for each subject. The average AUC for all subjects isdetermined by summing the AUCs of each subject and dividing the sum bythe number of subjects. The absolute value of the difference between thesubject's AUC and the average AUC is then determined for each subject.The absolute values of the differences obtained are then summed to givea value that represents the inter-subject variability. Lower valuesrepresent lower inter-subject variabilities and higher values representhigher inter-subject variabilities.

Mixtures of calcitonin drug-oligomer conjugates where each conjugate inthe mixture has the same molecular weight and has the structure ofFormula A according to embodiments of the present invention preferablyhave two or more of the above-described improved properties. Morepreferably, mixtures of calcitonin drug-oligomer conjugates where eachconjugate in the mixture has the same molecular weight and has thestructure of Formula A according to embodiments of the present inventionhave three or more of the above-described improved properties. Mostpreferably, mixtures of calcitonin drug-oligomer conjugates where eachconjugate in the mixture has the same molecular weight and has thestructure of Formula A according to embodiments of the present inventionhave four or more of the above-described improved properties.

Pharmaceutical compositions comprising a conjugate mixture according toembodiments of the present invention are also provided. The mixtures ofcalcitonin drug-oligomer conjugates described above may be formulatedfor administration in a pharmaceutical carrier in accordance with knowntechniques. See, e.g., Remington, The Science And Practice of Pharmacy(9^(th) Ed. 1995). In the manufacture of a pharmaceutical compositionaccording to embodiments of the present invention, the mixture ofcalcitonin drug-oligomer conjugates is typically admixed with, interalia, a pharmaceutically acceptable carrier. The carrier must, ofcourse, be acceptable in the sense of being compatible with any otheringredients in the pharmaceutical composition and should not bedeleterious to the patient. The carrier may be a solid or a liquid, orboth, and is preferably formulated with the mixture of calcitonindrug-oligomer conjugates as a unit-dose formulation, for example, atablet, which may contain from about 0.01 or 0.5% to about 95% or 99% byweight of the mixture of calcitonin drug-oligomer conjugates. Thepharmaceutical compositions may be prepared by any of the well knowntechniques of pharmacy including, but not limited to, admixing thecomponents, optionally including one or more accessory ingredients.

The pharmaceutical compositions according to embodiments of the presentinvention include those suitable for oral, rectal, topical, inhalation(e.g., via an aerosol) buccal (e.g., sub-lingual), vaginal, parenteral(e.g., subcutaneous, intramuscular, intradermal, intraarticular,intrapleural, intraperitoneal, inracerebral, intraarterial, orintravenous), topical (i.e., both skin and mucosal surfaces, includingairway surfaces) and transdermal administration, although the mostsuitable route in any given case will depend on the nature and severityof the condition being treated and on the nature of the particularmixture of calcitonin drug-oligomer conjugates which is being used.

Pharmaceutical compositions suitable for oral administration may bepresented in discrete units, such as capsules, cachets, lozenges, ortables, each containing a predetermined amount of the mixture ofcalcitonin drug-oligomer conjugates; as a powder or granules; as asolution or a suspension in an aqueous or non-aqueous liquid; or as anoil-in-water or water-in-oil emulsion. Such formulations may be preparedby any suitable method of pharmacy which includes the step of bringinginto association the mixture of calcitonin drug-oligomer conjugates anda suitable carrier (which may contain one or more accessory ingredientsas noted above). In general, the pharmaceutical composition according toembodiments of the present invention are prepared by uniformly andintimately admixing the mixture of calcitonin drug-oligomer conjugateswith a liquid or finely divided solid carrier, or both, and then, ifnecessary, shaping the resulting mixture. For example, a tablet may beprepared by compressing or molding a powder or granules containing themixture of calcitonin drug-oligomer conjugates, optionally with one ormore accessory ingredients. Compressed tablets may be prepared bycompressing, in a suitable machine, the mixture in a free-flowing form,such as a powder or granules optionally mixed with a binder, lubricant,inert diluent, and/or surface active/dispersing agent(s). Molded tabletsmay be made by molding, in a suitable machine, the powdered compoundmoistened with an inert liquid binder.

Pharmaceutical compositions suitable for buccal (sub-lingual)administration include lozenges comprising the mixture of calcitonindrug-oligomer conjugates in a flavoured base, usually sucrose and acaciaor tragacanth; and pastilles comprising the mixture of calcitonindrug-oligomer conjugates in an inert base such as gelatin and glycerinor sucrose and acacia.

Pharmaceutical compositions according to embodiments of the presentinvention suitable for parenteral administration comprise sterileaqueous and non-aqueous injection solutions of the mixture of calcitonindrug-oligomer conjugates, which preparations are preferably isotonicwith the blood of the intended recipient. These preparations may containanti-oxidants, buffers, bacteriostats and solutes which render thecomposition isotonic with the blood of the intended recipient. Aqueousand non-aqueous sterile suspensions may include suspending agents andthickening agents. The compositions may be presented in unit\dose ormulti-dose containers, for example sealed ampoules and vials, and may bestored in a freeze-dried (lyophilized) condition requiring only theaddition of the sterile liquid carrier, for example, saline orwater-for-injection immediately prior to use. Extemporaneous injectionsolutions and suspensions may be prepared from sterile powders, granulesand tablets of the kind previously described. For example, aninjectable, stable, sterile composition comprising a mixture ofcalcitonin drug-oligomer conjugates in a unit dosage form in a sealedcontainer may be provided. The mixture of calcitonin drug-oligomerconjugates is provided in the form of a lyophilizate which is capable ofbeing reconstituted with a suitable pharmaceutically acceptable carrierto form a liquid composition suitable for injection thereof into asubject. The unit dosage form typically comprises from about 10 mg toabout 10 grams of the mixture of calcitonin drug-oligomer conjugates.When the mixture of calcitonin drug-oligomer conjugates is substantiallywater-insoluble, a sufficient amount of emulsifying agent which isphysiologically acceptable may be employed in sufficient quantity toemulsify the mixture of calcitonin drug-oligomer conjugates in anaqueous carrier. One such useful emulsifying agent is phosphatidylcholine.

Pharmaceutical compositions suitable for rectal administration arepreferably presented as unit dose suppositories. These may be preparedby admixing the mixture of calcitonin drug-oligomer conjugates with oneor more conventional solid carriers, for example, cocoa butter, and thenshaping the resulting mixture.

Pharmaceutical compositions suitable for topical application to the skinpreferably take the form of an ointment, cream, lotion, paste, gel,spray, aerosol, or oil. Carriers which may be used include petroleumjelly, lanoline, polyethylene glycols, alcohols, transdermal enhancers,and combinations of two or more thereof.

Pharmaceutical compositions suitable for transdermal administration maybe presented as discrete patches adapted to remain in intimate contactwith the epidermis of the recipient for a prolonged period of time.Compositions suitable for transdermal administration may also bedelivered by iontophoresis (see, for example, Pharmaceutical Research 3(6):318 (1986)) and typically take the form of an optionally bufferedaqueous solution of the mixture of calcitonin drug-oligomer conjugates.Suitable formulations comprise citrate or bis\tris buffer (pH 6) orethanol/water and contain from 0.1 to 0.2M active ingredient.

Methods of treating a bone disorder in a subject in need of suchtreatment by administering an effective amount of such pharmaceuticalcompositions are also provided. The bone disorder is preferablycharacterized by excessive osteoclastic bone resorption and/orhypercalcemic serum effects. Bone disorders that may be treated and/orprevented by methods of the present invention include, but are notlimited to, osteoporosis, Paget's disease, and hypercalcemia.

The effective amount of any mixture of calcitonin drug-oligomerconjugates, the use of which is in the scope of present invention, willvary somewhat from mixture to mixture, and patient to patient, and willdepend upon factors such as the age and condition of the patient and theroute of delivery. Such dosages can be determined in accordance withroutine pharmacological procedures known to those skilled in the art. Asa general proposition, a dosage from about 0.1 to about 50 mg/kg willhave therapeutic efficacy, with all weights being calculated based uponthe weight of the mixture of calcitonin drug-oligomer conjugates.Toxicity concerns at the higher level may restrict intravenous dosagesto a lower level such as up to about 10 mg/kg, with all weights beingcalculated based upon the weight of the active base. A dosage from about10 mg/kg to about 50 mg/kg may be employed for oral administration.Typically, a dosage from about 0.5 mg/kg to 5 mg/kg may be employed forintramuscular injection. The frequency of administration is usually one,two, or three times per day or as necessary to control the condition.Alternatively, the drug-oligomer conjugates may be administered bycontinuous infusion. The duration of treatment depends on the type ofbone disorder being treated and may be for as long as the life of thepatient.

Methods of synthesizing conjugate mixtures according to embodiments ofthe present invention are also provided. While the following embodimentsof a synthesis route are directed to synthesis of a monodispersedmixture, similar synthesis routes may be utilized for synthesizing othercalcitonin drug-oligomer conjugate mixtures according to embodiments ofthe present invention.

A substantially monodispersed mixture of polymers comprisingpolyethylene glycol moieties is provided as illustrated in reaction 1:

R¹ is H or a lipophilic moiety. R¹ is preferably H, alkyl, aryl alkyl,an aromatic moiety, a fatty acid moiety, an ester of a fatty acidmoiety, cholesteryl, or adamantyl. R¹ is more preferably H, lower alkyl,or an aromatic moiety. R¹ is most preferably H, methyl, or benzyl.

In Formula I, n is from 1 to 25. Preferably n is from 1 to 6.

X⁺ is a positive ion. Preferably X⁺ is any positive ion in a compound,such as a strong base, that is capable of ionizing a hydroxyl moiety onPEG. Examples of positive ions include, but are not limited to, sodiumions, potassium ions, lithium ions, cesium ions, and thallium ions.

R² is H or a lipophilic moiety. R² is preferably linear or branchedalkyl, aryl alkyl, an aromatic moiety, a fatty acid moiety, or an esterof a fatty acid moiety. R² is more preferably lower alkyl, benzyl, afatty acid moiety having 1 to 24 carbon atoms, or an ester of a fattyacid moiety having 1 to 24 carbon atoms. R² is most preferably methyl, afatty acid moiety having 1 to 18 carbon atoms or an ethyl ester of afatty acid moiety having 1 to 18 carbon atoms.

In Formula II, m is from 1 to 25. Preferably m is from 1 to 6.

Ms is a mesylate moiety (i.e., CH₃S(O₂)—).

As illustrated in reaction 1, a mixture of compounds having thestructure of Formula I is reacted with a mixture of compounds having thestructure of Formula II to provide a mixture of polymers comprisingpolyethylene glycol moieties and having the structure of Formula III.The mixture of compounds having the structure of Formula I is asubstantially monodispersed mixture. Preferably, at least about 96, 97,98 or 99 percent of the compounds in the mixture of compounds of FormulaI have the same molecular weight, and, more preferably, the mixture ofcompounds of Formula I is a monodispersed mixture. The mixture ofcompounds of Formula II is a substantially monodispersed mixture.Preferably, at least about 96, 97, 98 or 99 percent of the compounds inthe mixture of compounds of Formula II have the same molecular weight,and, more preferably, the mixture of compounds of Formula II is amonodispersed mixture. The mixture of compounds of Formula III is asubstantially monodispersed mixture. Preferably, at least about 96, 97,98 or 99 percent of the compounds in the mixture of compound of FormulaIII have the same molecular weight. More preferably, the mixture ofcompounds of Formula III is a monodispersed mixture.

Reaction 1 is preferably performed between about 0° C. and about 40° C.,is more preferably performed between about 15° C. and about 35° C., andis most preferably performed at room temperature (approximately 25° C.).

Reaction 1 may be performed for various periods of time as will beunderstood by those skilled in the art. Reaction 1 is preferablyperformed for a period of time between about 0.25, 0.5 or 0.75 hours andabout 2, 4 or 8 hours.

Reaction 1 is preferably carried out in an aprotic solvent such as, butnot limited to, N,N-dimethylacetamide (DMA), N,N-dimethylformamide(DMF), dimethyl sulfoxide (DMSO), hexamethylphosphoric triamide,tetrahydrofuran (THF), dioxane, diethyl ether, methyl t-butyl ether(MTBE), toluene, benzene, hexane, pentane, N-methylpyrollidinone,tetrahydronaphthalene, decahydronaphthalene, 1,2-dichlorobenzene,1,3-dimethyl-2-imidazolidinone, or a mixture thereof. More preferably,the solvent is DMF, DMA or toluene.

The molar ratio of the compound of Formula I to the compound of FormulaII is preferably greater than about 1:1. More preferably, the molarratio is at least about 2:1. By providing an excess of the compounds ofFormula I, one can ensure that substantially all of the compounds ofFormula II are reacted, which may aid in the recovery of the compoundsof Formula III as discussed below.

Compounds of Formula I are preferably prepared as illustrated inreaction 2:

R¹ and X⁺ are as described above and the mixture of compounds of FormulaIV is substantially monodispersed; preferably, at least about 96, 97, 98or 99 percent of the compounds in the mixture of compounds of Formula IVhave the same molecular weight; and, more preferably, the mixture ofcompounds of Formula IV is a monodispersed mixture.

Various compounds capable of ionizing a hydroxyl moiety on the PEGmoiety of the compound of Formula IV will be understood by those skilledin the art. The compound capable of ionizing a hydroxyl moiety ispreferably a strong base. More preferably, the compound capable ofionizing a hydroxyl moiety is selected from the group consisting ofsodium hydride, potassium hydride, sodium t-butoxide, potassiumt-butoxide, butyl lithium (BuLi), and lithium diisopropylamine. Thecompound capable of ionizing a hydroxyl moiety is more preferably sodiumhydride.

The molar ratio of the compound capable of ionizing a hydroxyl moiety onthe PEG moiety of the compound of Formula IV to the compound of FormulaIV is preferably at least about 1:1, and is more preferably at leastabout 2:1. By providing an excess of the compound capable of ionizingthe hydroxyl moiety, it is assured that substantially all of thecompounds of Formula IV are reacted to provide the compounds of FormulaI. Thus, separation difficulties, which may occur if both compounds ofFormula IV and compounds of Formula I were present in the reactionproduct mixture, may be avoided.

Reaction 2 is preferably performed between about 0° C. and about 40° C.,is more preferably performed between about 0° C. and about 35° C., andis most preferably performed between about 0° C. and room temperature(approximately 25° C.).

Reaction 2 may be performed for various periods of time as will beunderstood by those skilled in the art. Reaction 2 is preferablyperformed for a period of time between about 0.25, 0.5 or 0.75 hours andabout 2, 4 or 8 hours.

Reaction 2 is preferably carried out in an aprotic solvent such as, butnot limited to, N,N-dimethylacetamide (DMA), N,N-dimethylformamide(DMF), dimethyl sulfoxide (DMSO), hexamethylphosphoric triamide,tetrahydrofuran (THF), dioxane, diethyl ether, methyl t-butyl ether(MTBE), toluene, benzene, hexane, pentane, N-methylpyrollidinone,dichloromethane, chloroform, tetrahydronaphthalene,decahydronaphthalene, 1,2-dichlorobenzene,1,3-dimethyl-2-imidazolidinone, or a mixture thereof. More preferably,the solvent is DMF, dichloromethane or toluene.

Compounds of Formula II are preferably prepared as illustrated inreaction 3:

R² and Ms are as described above and the compound of Formula V ispresent as a substantially monodispersed mixture of compounds of FormulaV; preferably at least about 96, 97, 98 or 99 percent of the compoundsin the mixture of compounds of Formula V have the same molecular weight;and, more preferably, the mixture of compounds of Formula V is amonodispersed mixture.

Q is a halide? preferably chloride or fluoride.

CH₃S(O₂)Q is methanesulfonyl halide. The methanesulfonyl halide ispreferably methanesulfonyl chloride or methanesulfonyl fluoride. Morepreferably, the methanesulfonyl halide is methanesulfonyl chloride.

The molar ratio of the methane sulfonyl halide to the compound ofFormula V is preferably greater than about 1:1, and is more preferablyat least about 2:1. By providing an excess of the methane sulfonylhalide, it is assured that substantially all of the compounds of FormulaV are reacted to provide the compounds of Formula II. Thus, separationdifficulties, which may occur if both compounds of Formula V andcompounds of Formula II were present in the reaction product mixture,may be avoided.

Reaction 3 is preferably performed between about −10° C. and about 40°C., is more preferably performed between about 0° C. and about 35° C.,and is most preferably performed between about 0° C. and roomtemperature (approximately 25° C.).

Reaction 3 may be performed for various periods of time as will beunderstood by those skilled in the art. Reaction 3 is preferablyperformed for a period of time between about 0.25, 0.5 or 0.75 hours andabout 2, 4 or 8 hours.

Reaction 3 is preferably carried out in the presence of an aliphaticamine including, but not limited to, monomethylamine, dimethylamine,trimethylamine, monoethylamine, diethylamine, triethylamine,monoisopropylamine, diisopropylamine, mono-n-butylamine,di-n-butylamine, tri-n-butylamine, monocyclohexylamine,dicyclohexylamine, or mixtures thereof. More preferably, the aliphaticamine is a tertiary amine such as triethylamine.

As will be understood by those skilled in the art, various substantiallymonodispersed mixtures of compounds of Formula V are commerciallyavailable. For example, when R² is H or methyl, the compounds of FormulaV are PEG or mPEG compounds, respectively, which are commerciallyavailable from Aldrich of Milwaukee, Wis.; Fluka of Switzerland, and/orTCl America of Portland, Oreg.

When R² is a lipophilic moiety such as, for example, higher alkyl, fattyacid, an ester of a fatty acid, cholesteryl, or adamantyl, the compoundsof Formula V may be provided by various methods as will be understood bythose skilled in the art. The compounds of Formula V are preferablyprovided as follows:

R² is a lipophilic moiety, preferably higher alkyl, fatty acid ester,cholesteryl, or adamantyl, more preferably a lower alkyl ester of afatty acid, and most preferably an ethyl ester of a fatty acid havingfrom 1 to 18 carbon atoms.

R³ is H, benzyl, trityl, tetrahydropyran, or other alcohol protectinggroups as will be understood by those skilled in the art.

X₂ ⁺ is a positive ion as described above with respect to X⁺.

The value of m is as described above.

Regarding reaction 4, a mixture of compounds of Formula VI is reactedwith a mixture of compounds of Formula VII under reaction conditionssimilar to those described above with reference to reaction 1. Themixture of compounds of Formula VI is a substantially monodispersedmixture. Preferably, at least about 96, 97, 98 or 99 percent of thecompounds in the mixture of compounds of Formula VI have the samemolecular weight. More preferably, the mixture of compounds of FormulaVI is a monodispersed mixture. The mixture of compounds of Formula VIIis a substantially monodispersed mixture. Preferably, at least about 96,97, 98 or 99 percent of the compounds in the mixture of compounds ofFormula VII have the same molecular weight. More preferably, the mixtureof compounds of Formula VII is a monodispersed mixture.

Regarding reaction 5, the compound of Formula VIII may be hydrolyzed toconvert the R³ moiety into an alcohol by various methods as will beunderstood by those skilled in the art. When R³ is benzyl or trityl, thehydrolysis is preferably performed utilizing H₂ in the presence of apalladium-charcoal catalyst as is known by those skilled in the art. Ofcourse, when R³ is H, reaction 5 is unnecessary.

The compound of Formula VI may be commercially available or be providedas described above with reference to reaction 3. The compound of FormulaVII may be provided as described above with reference to reaction 2.

Substantially monodispersed mixtures of polymers comprising PEG moietiesand having the structure of Formula III above can further be reactedwith other substantially monodispersed polymers comprising PEG moietiesin order to extend the PEG chain. For example, the following scheme maybe employed:

Ms, m and n are as described above with reference to reaction 1; p issimilar to n and m, and X₂ ⁺ is similar to X⁺ as described above withreference to reaction 1. Q is as described above with reference toreaction 3. R² is as described above with reference to reaction 1 and ispreferably lower alkyl. R¹ is H. Reaction 6 is preferably performed in amanner similar to that described above with reference to reaction 3.Reaction 7 is preferably performed in a manner similar to that describedabove with reference to reaction 1. Preferably, at least about 96, 97,98 or 99 percent of the compounds in the mixture of compounds of FormulaIII have the same molecular weight, and, more preferably, the mixture ofcompounds of Formula III is a monodispersed mixture. The mixture ofcompounds of Formula X is a substantially monodispersed mixture.Preferably, at least about 96, 97, 98 or 99 percent of the compounds inthe mixture of compounds of Formula X have the same molecular weight,and, more preferably, the mixture of compounds of Formula X is amonodispersed mixture.

A process according to embodiments of the present invention isillustrated by the scheme shown in FIG. 1, which will now be described.The synthesis of substantially monodispersed polyethyleneglycol-containing oligomers begins by the preparation of the monobenzylether (1) of a substantially monodispersed polyethylene glycol. Anexcess of a commercially available substantially monodispersedpolyethylene glycol is reacted with benzyl chloride in the presence ofaqueous sodium hydroxide as described by Coudert et al (SyntheticCommunications, 16(1): 19–26 (1986)). The sodium salt of 1 is thenprepared by the addition of NaH, and this sodium salt is allowed toreact with the mesylate synthesized from the ester of a hydroxyalkanoicacid (2). The product (3) of the displacement of the mesylate isdebenzylated via catalytic hydrogenation to obtain the alcohol (4). Themesylate (5) of this alcohol may be prepared by addition ofmethanesulfonyl chloride and used as the electrophile in the reactionwith the sodium salt of the monomethyl ether of a substantiallymonodispersed polyethylene glycol derivative, thereby extending thepolyethylene glycol portion of the oligomer to the desired length,obtaining the elongated ester (6). The ester may be hydrolyzed to theacid (7) in aqueous base and transformed into the activated ester (8) byreaction with a carbodiimide and N-hydroxysuccinimide. While theoligomer illustrated in FIG. 1 is activated using N-hydroxysuccinimide,it is to be understood that various other reagents may be used toactivate oligomers of the present invention including, but not limitedto, active phenyl chloroformates such as para-nitrophenyl chloroformate,phenyl chloroformate, 3,4-phenyldichloroformate, and3,4-phenyldichloroformate; tresylation; and acetal formation.

Still referring to FIG. 1, q is from 1 to 24. Preferably, q is from 1 to18, and q is more preferably from 4 to 16. R⁴ is a moiety capable ofundergoing hydrolysis to provide the carboxylic acid. R⁴ is preferablylower alkyl and is more preferably ethyl. The variables n and m are asdescribed above with reference to reaction 1.

All starting materials used in the procedures described herein areeither commercially available or can be prepared by methods known in theart using commercially available starting materials.

The present invention will now be described with reference to thefollowing examples. It should be appreciated that these examples are forthe purposes of illustrating aspects of the present invention, and donot limit the scope of the invention as defined by the claims.

EXAMPLES Examples 1 through 10

Reactions in Examples 1 through 10 were carried out under nitrogen withmagnetic stirring, unless otherwise specified. “Work-up” denotesextraction with an organic solvent, washing of the organic phase withsaturated NaCl solution, drying (MgSO₄), and evaporation (rotaryevaporator). Thin layer chromatography was conducted with Merck glassplates precoated with silica gel 60° F.-254 and spots were visualized byiodine vapor. All mass spectra were determined by MacromolecularResources Colorado State University, CO and are reported in the orderm/z, (relative intensity). Elemental analyses and melting points wereperformed by Galbraith Laboratories, Inc., Knoxyille, Tenn. Examples1–10 refer to the scheme illustrated in FIG. 2.

Example 1 8-Methoxy-1-(methylsulfonyl)oxy-3,6-dioxaoctane (9)

A solution of non-polydispersed triethylene glycol monomethyl ethermolecules (4.00 mL, 4.19 g, 25.5 mmol) and triethylamine (4.26 mL, 3.09g, 30.6 mmol) in dry dichloromethane (50 mL) was chilled in an ice bathand place under a nitrogen atmosphere. A solution of methanesulfonylchloride (2.37 mL, 3.51 g, 30.6 mmol) in dry dichloromethane (20 mL) wasadded dropwise from an addition funnel. Ten minutes after the completionof the chloride addition, the reaction mixture was removed from the icebath and allowed to come to room temperature. The mixture was stirredfor an additional hour, at which time TLC (CHCl₃ with 15% MeOH as theelutant) showed no remaining triethylene glycol monomethyl ether.

The reaction mixture was diluted with another 75 mL of dichloromethaneand washed successively with saturated NaHCO₃, water and brine. Theorganics were dried over Na₂SO₄, filtered and concentrated in vacuo togive a non-polydispersed mixture of compounds 9 as a clear oil (5.31 g,86%).

Example 2 Ethylene Glycol Mono Methyl Ether (10) (m=4,5,6)

To a stirred solution of non-polydispersed compound 11 (35.7 mmol) indry DMF (25.7 mL), under N₂ was added in portion a 60% dispersion of NaHin mineral oil, and the mixture was stirred at room temperature for 1hour. To this salt 12 was added a solution of non-polydispersed mesylate9 (23.36) in dry DMF (4 ml) in a single portion, and the mixture wasstirred at room temperature for 3.5 hours. Progress of the reaction wasmonitored by TLC (12% CH₃OH—CHCl₃). The reaction mixture was dilutedwith an equal amount of 1N HCl, and extracted with ethyl acetate (2×20ml) and discarded. Extraction of aqueous solution and work-up gavenon-polydispersed polymer 10 (82–84% yield).

Example 3 3,6,9,12,15,18,21-Heptaoxadocosanol (10) (m=4)

Oil; Rf 0.46 (methanol:chloroform=3:22); MS m/z calc'd for C₁₅H₃₂O₈340.21 (M⁺+1), found 341.2.

Example 4 3,6,9,12,15,18,21,24-Octaoxapentacosanol (10) (m=5)

Oil; Rf 0.43 (methanol:chloroform=6:10); MS m/z calc'd for C₁₇H₃₆O₉384.24 (M⁺+1), found 385.3.

Example 5 3,6,9,12,15,18,21,24,27-Nonaoxaoctacosanol (10) (m=6)

Oil; Rf 0.42 (methanol:chloroform=6:10); MS m/z calc'd for C₁₉H₄₀O₁₀428.26 (M⁺+1), found 429.3.

Example 620-methoxy-1-(methylsulfonyl)oxy-3,6,9,12,15,18-hexaoxaeicosane (14)

Non-polydispersed compound 14 was obtained in quantitative yield fromthe alcohol 13 (m=4) and methanesulfonyl chloride as described for 9, asan oil; Rf 0.4 (ethyl acetate:acetonitrile=1:5); MS m/z calc'd forC₁₇H₃₇O₁₀ 433.21 (M⁺+1), found 433.469.

Example 7 Ethylene Glycol Mono Methyl Ether (15) (m=3,4,5)

The non-polydispersed compounds 15 were prepared from a diol by usingthe procedure described above for compound 10.

Example 8 3,6,9,12,15,18,21,24,27,30-Decaoxaheneicosanol (15) (m=3)

Oil; Rf 0.41 (methanol:chloroform=6:10); MS m/z calc'd for C₂₁H₄₄O₁₁472.29 (M⁺+1), found 472.29.

Example 9 3,6,9,12,15,18,21,24,27,30,33-Unecaoxatetratricosanol (15)(m=4)

Oil; Rf 0.41 (methanol:chloroform=6:10); MS m/z calc'd for C₂₃H₄₈O₁₂516.31 (M⁺+1), found 516.31.

Example 10 3,6,9,12,15,18,21,24,27,30,33,36-Dodecaoxaheptatricosanol(15) (m=5) Oil; Rf 0.41 (methanol:chloroform=6:10); MS m/z calc'd forC₂₅H₅₂O₁₃ 560.67 (M++1), found 560.67.

Examples 11 through 18 refer to the scheme illustrated in FIG. 3.

Example 11 Hexaethylene Glycol Monobenzyl Ether (16)

An aqueous sodium hydroxide solution prepared by dissolving 3.99 g (100mmol) NaOH in 4 ml water was added slowly to non-polydispersedhexaethylene glycol (28.175 g, 25 ml, 100 mmol). Benzyl chloride (3.9 g,30.8 mmol, 3.54 ml) was added and the reaction mixture was heated withstirring to 100° C. for 18 hours. The reaction mixture was then cooled,diluted with brine (250 ml) and extracted with methylene chloride (200ml×2). The combined organic layers were washed with brine once, driedover Na₂SO₄, filtered and concentrated in vacuo to a dark brown oil. Thecrude product mixture was purified via flash chromatography (silica gel,gradient elution: ethyl acetate to 9/1 ethyl acetate/methanol) to yield8.099 g (70%) of non-polydispersed 16 as a yellow oil.

Example 12 Ethyl 6-methylsulfonyloxyhexanoate (17)

A solution of non-polydispersed ethyl 6-hydroxyhexanoate (50.76 ml,50.41 g, 227 mmol) in dry dichloromethane (75 ml) was chilled in a icebath and placed under a nitrogen atmosphere. Triethylamine (34.43 ml,24.99 g, 247 mmol) was added. A solution of methanesulfonyl chloride(19.15 ml, 28.3 g, 247 mmol) in dry dichloromethane (75 ml) was addeddropwise from an addition funnel. The mixture was stirred for three andone half hours, slowly being allowed to come to room temperature as theice bath melted. The mixture was filtered through silica gel, and thefiltrate was washed successively with water, saturated NaHCO₃, water andbrine. The organics were dried over Na₂SO₄, filtered and concentrated invacuo to a pale yellow oil. Final purification of the crude product wasachieved by flash chromatography (silica gel, 1/1 hexanes/ethyl acetate)to give the non-polydispersed product (46.13 g, 85%) as a clear,colorless oil. FAB MS: m/e 239 (M+H), 193 (M-C₂H₅O).

Example 136-{2-[2-(2-{2-[2-(2-Benzyloxyethoxy)ethoxy]ethoxy}-ethoxy)-ethoxy]-ethoxy}-hexanoicacid ethyl ester (18)

Sodium hydride (3.225 g or a 60% oil dispersion, 80.6 mmol) wassuspended in 80 ml of anhydrous toluene, placed under a nitrogenatmosphere and cooled in an ice bath. A solution of thenon-polydispersed alcohol 16 (27.3 g, 73.3 mmol) in 80 ml dry toluenewas added to the NaH suspension. The mixture was stirred at 0° C. forthirty minutes, allowed to come to room temperature and stirred foranother five hours, during which time the mixture became a clear brownsolution. The non-polydispersed mesylate 17 (19.21 g, 80.6 mmol) in 80ml dry toluene was added to the NaH/alcohol mixture, and the combinedsolutions were stirred at room temperature for three days. The reactionmixture was quenched with 50 ml methanol and filtered through basicalumina. The filtrate was concentrated in vacuo and purified by flashchromatography (silica gel, gradient elution: 3/1 ethyl acetate/hexanesto ethyl acetate) to yield the non-polydispersed product as a paleyellow oil (16.52 g, 44%). FAB MS: m/e 515 (M+H).

Example 146-{2-[2-(2-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}-ethoxy)-ethoxy]-ethoxy}-hexanoicacid ethyl ester (19)

Non-polydispersed benzyl ether 18 (1.03 g, 2.0 mmol) was dissolved in 25ml ethanol. To this solution was added 270 mg 10% Pd/C, and the mixturewas placed under a hydrogen atmosphere and stirred for four hours, atwhich time TLC showed the complete disappearance of the startingmaterial. The reaction mixture was filtered through Celite 545 to removethe catalyst, and the filtrate was concentrated in vacuo to yield thenon-polydispersed title compound as a clear oil (0.67 g, 79%). FAB MS:m/e 425 (M+H), 447 (M+Na).

Example 156-{2-[2-(2-{2-[2-(2-methylsulfonylethoxy)ethoxy]ethoxy}-ethoxy)-ethoxy]-ethoxy}-hexanoicacid ethyl ester (20)

The non-polydispersed alcohol 19 (0.835 g, 1.97 mmol) was dissolved in3.5 ml dry dichloromethane and placed under a nitrogen atmosphere.Triethylamine (0.301 ml, 0.219 g, 2.16 mmol) was added and the mixturewas chilled in an ice bath. After two minutes, the methanesulfonylchloride (0.16 ml, 0.248 g, 2.16 mmol) was added. The mixture wasstirred for 15 minutes at 0° C., then at room temperature for two hours.The reaction mixture was filtered through silica gel to remove thetriethylammonium chloride, and the filtrate was washed successively withwater, saturated NaHCO₃, water and brine. The organics were dried overNa₂SO₄, filtered and concentrated in vacuo. The residue was purified bycolumn chromatography (silica gel, 9/1 ethyl acetate/methanol) to givenon-polydispersed compound 20 as a clear oil (0.819 g, 83%). FAB MS: m/e503 (M+H).

Example 166-(2-{2-[2-(2-{2-[2-(2-methoxyethoxy)ethoxy]-ethoxy}-ethoxy)-ethoxy]-ethoxy}-ethoxy)-hexanoicacid ethyl ester (21)

NaH (88 mg of a 60% dispersion in oil, 2.2 mmol) was suspended inanhydrous toluene (3 ml) under N₂ and chilled to 0° C. Non-polydisperseddiethylene glycol monomethyl ether (0.26 ml, 0.26 g, 2.2 mmol) that hadbeen dried via azeotropic distillation with toluene was added. Thereaction mixture was allowed to warm to room temperature and stirred forfour hours, during which time the cloudy grey suspension became clearand yellow and then turned brown. Mesylate 20 (0.50 g, 1.0 mmol) in 2.5ml dry toluene was added. After stirring at room temperature over night,the reaction was quenched by the addition of 2 ml of methanol and theresultant solution was filtered through silica gel. The filtrate wasconcentrated in vacuo and the FAB MS: m/e 499 (M+H), 521 (M+Na).Additional purification by preparatory chromatography (silica gel, 19/3chloroform/methanol) provided the non-polydispersed product as a clearyellow oil (0.302 g 57%). FAB MS: m/e 527 (M+H), 549 (M+Na).

Example 176-(2-{2-[2-(2-{2-[2-(2-methoxyethoxy)ethoxy]-ethoxy}-ethoxy)-ethoxy]-ethoxy}-ethoxy)-hexanoicacid (22)

Non-polydispersed ester 21 (0.25 g, 0.46 mmol) was stirred for 18 hoursin 0.71 ml of 1 N NaOH. After 18 hours, the mixture was concentrated invacuo to remove the alcohol and the residue dissolved in a further 10 mlof water. The aqueous solution was acidified to pH 2 with 2 N HCl andthe product was extracted into dichloromethane (30 ml×2). The combinedorganics were then washed with brine (25 ml×2), dried over Na₂SO₄,filtered and concentrated in vacuo to yield the non-polydispersed titlecompound as a yellow oil (0.147 g, 62%). FAB MS: m/e 499 (M+H), 521(M+Na).

Example 186-(2-{2-[2-(2-{2-[2-(2-methoxyethoxy)ethoxy]-ethoxy}-ethoxy)-ethoxy]-ethoxy}-ethoxy)-hexanoic acid 2,5-dioxo-pyrrolidin-1-yl ester (23)

Non-polydispersed acid 22 (0.209 g, 0.42 mmol) were dissolved in 4 ml ofdry dichloromethane and added to a dry flask already containingNHS(N-hydroxysuccinimide) (57.8 mg, 0.502 mmol) and EDC(1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) (98.0 mg,0.502 mmol) under a N₂ atmosphere. The solution was stirred at roomtemperature overnight and filtered through silica gel to remove excessreagents and the urea formed from the EDC. The filtrate was concentratedin vacuo to provide the non-polydispersed product as a dark yellow oil(0.235 g, 94%). FAB MS: m/e 596 (M+H), 618 (M+Na).

Examples 19 through 24 refer to the scheme illustrated in FIG. 4.

Example 19 Mesylate of Triethylene Glycol Monomethyl Ether (24)

To a solution of CH₂Cl₂ (100 mL) cooled to 0° C. in an ice bath wasadded non-polydispersed triethylene glycol monomethyl ether (25 g, 0.15mol). Then triethylamine (29.5 mL, 0.22 mol) was added and the solutionwas stirred for 15 min at 0° C., which was followed by dropwise additionof methanesulfonyl chloride (13.8 mL, 0.18 mol, dissolved in 20 mLCH₂Cl₂). The reaction mixture was stirred for 30 min at 0° C., allowedto warm to room temperature, and then stirred for 2 h. The crudereaction mixture was filtered through Celite (washed CH₂Cl₂˜200 mL),then washed with H₂O (300 mL), 5% NaHCO₃ (300 mL), H₂O (300 mL), sat.NaCl (300 mL), dried MgSO₄, and evaporated to dryness. The oil was thenplaced on a vacuum line for ˜2 h to ensure dryness and afforded thenon-polydispersed title compound as a yellow oil (29.15 g, 80% yield).

Example 20 Heptaethylene Glycol Monomethyl Ether (25)

To a solution of non-polydispersed tetraethylene glycol (51.5 g, 0.27mol) in THF (1 L) was added potassium t-butoxide (14.8 g, 0.13 mol,small portions over 30 min). The reaction mixture was then stirred for 1h and then 24 (29.15 g, 0.12 mol) dissolved in THF (90 mL) was addeddropwise and the reaction mixture was stirred overnight. The crudereaction mixture was filtered through Celite (washed CH₂Cl₂, ˜200 mL)and evaporated to dryness. The oil was then dissolved in HCl (250 mL,1N) and washed with ethyl acetate (250 mL) to remove excess 24.Additional washings of ethyl acetate (125 mL) may be required to removeremaining 24. The aqueous phase was washed repetitively with CH₂Cl₂ (125mL volumes) until most of the 25 has been removed from the aqueousphase. The first extraction will contain 24, 25, and dicoupled sideproduct and should be back extracted with HCl (125 mL, 1N). The organiclayers were combined and evaporated to dryness. The resultant oil wasthen dissolved in CH₂Cl₂ (100 mL) and washed repetitively with H₂O (50mL volumes) until 25 was removed. The aqueous fractions were combined,total volume 500 mL, and NaCl was added until the solution became cloudyand then was washed with CH₂Cl₂ (2×500 mL). The organic layers werecombined, dried MgSO₄, and evaporated to dryness to afford a thenon-polydispersed title compound as an oil (16.9 g, 41% yield). It maybe desirable to repeat one or more steps of the purification procedureto ensure high purity.

Example 21 8-Bromooctoanate (26)

To a solution of 8-bromooctanoic acid (5.0 g, 22 mmol) in ethanol (100mL) was added H₂SO₄ (0.36 mL, 7.5 mmol) and the reaction was heated toreflux with stirring for 3 h. The crude reaction mixture was cooled toroom temperature and washed H₂O (100 mL), sat. NaHCO₃ (2×100 mL), H₂O(100 mL), dried MgSO₄, and evaporated to dryness to afford a clear oil(5.5 g, 98% yield).

Example 22 Synthesis of MPEG7-C8 Ester (27)

To a solution of the non-polydispersed compound 25 (3.0 g, 8.8 mmol) inether (90 mL) was added potassium t-butoxide (1.2 g, 9.6 mmol) and thereaction mixture was stirred for 1 h. Then dropwise addition of thenon-polydispersed compound 26 (2.4 g, 9.6 mmol), dissolved in ether (10mL), was added and the reaction mixture was stirred overnight. The crudereaction mixture was filtered through Celite (washed CH₂Cl₂, ˜200 mL)and evaporated to dryness. The resultant oil was dissolved in ethylacetate and washed H₂O (2×200 mL), dried MgSO₄, and evaporated todryness. Column chromatography (Silica, ethyl acetate to ethylacetate/methanol, 10:1) was performed and afforded the non-polydispersedtitle compound as a clear oil (0.843 g, 19% yield).

Example 23 MPEG7-C8 Acid (28)

To the oil of the non-polydispersed compound 27 (0.70 g, 1.4 mmol) wasadded 1N NaOH (2.0 mL) and the reaction mixture was stirred for 4 h. Thecrude reaction mixture was concentrated, acidified (pH˜2), saturatedwith NaCl, and washed CH₂Cl₂ (2×50 mL). The organic layers werecombined, washed sat. NaCl, dried MgSO₄, and evaporated to dryness toafford the non-polydispersed title compound as a clear oil (0.35 g, 53%yield).

Example 24 Activation of MPEG7-C8 Acid (29)

Non-polydispersed mPEG7-C8-acid 28 (0.31 g, 0.64 mmol) was dissolved in3 ml of anhydrous methylene chloride and then solution ofN-hydroxysuccinimide (0.079 g, 0.69 mmol) and EDCI·HCl (135.6 mg, 0.71mmol) in anhydrous methylene chloride added. Reaction was stirred forseveral hours, then washed with 1N HCl, water, dried over MgSO₄,filtered and concentrated. Crude material was purified by columnchromatography, concentrated to afford the non-polydispersed titlecompound as a clear oil and dried via vacuum.

Examples 25 through 29 refer to the scheme illustrated in FIG. 5.

Example 25 10-hydroxydecanoate (30)

To a solution of non-polydispersed 10-hydroxydecanoic acid (5.0 g, 26.5mmol) in ethanol (100 mL) was added H₂SO₄ (0.43 mL, 8.8 mmol) and thereaction was heated to reflux with stirring for 3 h. The crude reactionmixture was cooled to room temperature and washed H₂O (100 mL), sat.NaHCO₃ (2×100 mL), H₂O (100 mL), dried MgSO₄, and evaporated to drynessto afford the non-polydispersed title compound as a clear oil (6.9 g,98% yield).

Example 26 Mesylate of 10-hydroxydecanoate (31)

To a solution of CH₂Cl₂ (27 mL) was added non-polydispersed10-hydroxydecanoate 30 (5.6 g, 26 mmol) and cooled to 0° C. in an icebath. Then triethylamine (5 mL, 37 mmol) was added and the reactionmixture was stirred for 15 min at 0° C. Then methanesulfonyl chloride(2.7 mL, 24 mmol) dissolved in CH₂Cl₂ (3 mL) was added and the reactionmixture was stirred at 0° C. for 30 min, the ice bath was removed andthe reaction was stirred for an additional 2 h at room temperature. Thecrude reaction mixture was filtered through Celite (washed CH₂Cl₂, 80mL) and the filtrate was washed H₂O (100 mL), 5% NaHCO₃ (2×100 mL), H₂O(100 mL), sat. NaCl (100 mL), dried MgSO₄, and evaporated to dryness toafford the non-polydispersed title compound as a yellowish oil (7.42 g,97% yield).

Example 27 MPEG₇-C₁₀ Ester (32)

To a solution of non-polydispersed heptaethylene glycol monomethyl ether25 (2.5 g, 7.3 mmol) in tetrahydrofuran (100 mL) was added sodiumhydride (0.194 g, 8.1 mmol) and the reaction mixture was stirred for 1h. Then dropwise addition of mesylate of non-polydispersed10-hydroxydecanoate 31 (2.4 g, 8.1 mmol), dissolved in tetrahydrofuran(10 mL), was added and the reaction mixture was stirred overnight. Thecrude reaction mixture was filtered through Celite (washed CH₂Cl₂, ˜200mL) and evaporated to dryness. The resultant oil was dissolved in ethylacetate and washed H₂O (2×200 mL), dried MgSO₄, evaporated to dryness,chromatographed (silica, ethyl acetate/methanol, 10:1), andchromatographed (silica, ethyl acetate) to afford the non-polydispersedtitle compound as a clear oil (0.570 g, 15% yield).

Example 28 MPEG₇-C₁₀ Acid (33)

To the oil of non-polydispersed mPEG₇-C₁₀ ester 32 (0.570 g, 1.1 mmol)was added 1N NaOH (1.6 mL) and the reaction mixture was stirredovernight. The crude reaction mixture was concentrated, acidified(pH˜2), saturated with NaCl, and washed CH₂Cl₂ (2×50 mL). The organiclayers were combined, washed sat. NaCl (2×50 mL), dried MgSO₄, andevaporated to dryness to afford the non-polydispersed title compound asa clear oil (0.340 g, 62% yield).

Example 29 Activation of MPEG₇-C₁₀ Acid (34)

The non-polydispersed acid 33 was activated using procedures similar tothose described above in Example 24.

Examples 30 and 31 refer to the scheme illustrated in FIG. 6.

Example 30 Synthesis of C18(PEG6) Oligomer (36)

Non-polydispersed stearoyl chloride 35 (0.7 g, 2.31 mmol) was addedslowly to a mixture of PEG6 (5 g, 17.7 mmol) and pyridine (0.97 g, 12.4mmol) in benzene. The reaction mixture was stirred for several hours(˜5). The reaction was followed by TLC using ethylacetate/methanol as adeveloping solvent. Then the reaction mixture was washed with water,dried over MgSO₄, concentrated and dried via vacuum. Purifiednon-polydispersed compound 36 was analyzed by FABMS: m/e 549/M⁺H.

Example 31 Activation of C18(PEG6) Oligomer

Activation of non-polydispersed C 18(PEG6) oligomer was accomplished intwo steps:

1) Non-polydispersed stearoyl-PEG6 36 (0.8 g, 1.46 mmol) was dissolvedin toluene and added to a phosgene solution (10 ml, 20% in toluene)which was cooled with an ice bath. The reaction mixture was stirred for1 h at 0° C. and then for 3 h at room temperature. Then phosgene andtoluene were distilled off and the remaining non-polydispersed stearoylPEG6 chloroformate 37 was dried over P₂O₅ overnight.

2) To a solution of non-polydispersed stearoyl PEG6 chloroformate 36(0.78 g, 1.27 mmol) and TEA (128 mg, 1.27 mmol) in anhydrous methylenechloride, N-hydroxy succinimide (NHS) solution in methylene chloride wasadded. The reaction mixture was stirred for 16 hours, then washed withwater, dried over MgSO₄, filtered, concentrated and dried via vacuum toprovide the non-polydispersed activated C18(PEG6) oligomer 38.

Examples 32 through 37 refer to the scheme illustrated in FIG. 7.

Example 32 Tetraethylene Glycol Monobenzylether (39)

To the oil of non-polydispersed tetraethylene glycol (19.4 g, 0.10 mol)was added a solution of NaOH (4.0 g in 4.0 mL) and the reaction wasstirred for 15 mm. Then benzyl chloride (3.54 mL, 30.8 mmol) was addedand the reaction mixture was heated to 100° C. and stirred overnight.The reaction mixture was cooled to room temperature, diluted with sat.NaCl (250 mL), and washed CH₂Cl₂ (2×200 mL). The organic layers werecombined, washed sat. NaCl, dried MgSO₄, and chromatographed (silica,ethyl acetate) to afford the non-polydispersed title compound as ayellow oil (6.21 g, 71% yield).

Example 33 Mesylate of Tetraethylene Glycol Monobenzylether (40)

To a solution of CH₂Cl₂ (20 mL) was added non-polydispersedtetraethylene glycol monobenzylether 39 (6.21 g, 22 mmol) and cooled to0° C. in an ice bath. Then triethylamine (3.2 mL, 24 mmol) was added andthe reaction mixture was stirred for 15 min at 0° C. Thenmethanesulfonyl chloride (1.7 mL, 24 mmol) dissolved in CH₂Cl₂ (2 mL)was added and the reaction mixture was stirred at 0° C. for 30 min, theice bath was removed and the reaction was stirred for an additional 2 hat room temperature. The crude reaction mixture was filtered throughCelite (washed CH₂Cl₂, 80 mL) and the filtrate was washed H₂O (100 mL),5% NaHCO₃ (2×100 mL), H₂O (100 mL), sat. NaCl (100 mL), and dried MgSO₄.The resulting yellow oil was chromatographed on a pad of silicacontaining activated carbon (10 g) to afford the non-polydispersed titlecompound as a clear oil (7.10 g, 89% yield).

Example 34 Octaethylene Glycol Monobenzylether (41)

To a solution of tetrahydrofuran (140 mL) containing sodium hydride(0.43 g, 18 mmol) was added dropwise a solution of non-polydispersedtetraethylene glycol (3.5 g, 18 mmol) in tetrahydrofuran (10 mL) and thereaction mixture was stirred for 1 h. Then mesylate of non-polydispersedtetraethylene glycol monobenzylether 40 (6.0 g, 16.5 mmol) dissolved intetrahydrofuran (10 mL) was added dropwise and the reaction mixture wasstirred overnight. The crude reaction mixture was filtered throughCelite (washed, CH₂Cl₂, 250 mL) and the filtrate was washed H₂O, driedMgSO₄, and evaporated to dryness. The resultant oil was chromatographed(silica, ethyl acetate/methanol, 10:1) and chromatographed (silica,chloroform/methanol, 25:1) to afford the non-polydispersed titlecompound as a clear oil (2.62 g, 34% yield).

Example 35 Synthesis of Stearate PEG8-Benzyl (43)

To a stirred cooled solution of non-polydispersed octaethylene glycolmonobenzylether 41 (0.998 g, 2.07 mmol) and pyridine (163.9 mg, 2.07mmol) was added non-polydispersed stearoyl chloride 42 (627.7 mg, 2.07mmol) in benzene. The reaction mixture was stirred overnight (18 hours).The next day the reaction mixture was washed with water, dried overMgSO₄, concentrated and dried via vacuum. Then the crude product waschromatographed on flash silica gel column, using 10% methanol/90%chloroform. The fractions containing the product were combined,concentrated and dried via vacuum to afford the non-polydispersed titlecompound.

Example 36 Hydrogenolysis of Stearate-PEG8-Benzyl

To a methanol solution of non-polydispersed stearate-PEG8-Bzl 43 (0.8⁵4g 1.138 mmol) Pd/C(10%) (palladium, 10% wt. on activated carbon) wasadded. The reaction mixture was stirred overnight (18 hours) underhydrogen. Then the solution was filtered, concentrated and purified byflash column chromatography using 10% methanol/90% chloroform, fractionswith R_(t)=0.6 collected, concentrated and dried to provide thenon-polydispersed acid 44.

Example 37 Activation of C18(PEG8) Oligomer

Two step activation of non-polydispersed stearate-PEG8 oligomer wasperformed as described for stearate-PEG6 in Example 31 above to providethe non-polydispersed activated C 18(PEG8) oligomer 45.

Example 38 Synthesis of Activated Triethylene Glycol MonomethylOligomers

The following description refers to the scheme illustrated in FIG. 8. Asolution of toluene containing 20% phosgene (100 ml, approximately 18.7g, 189 mmol phosgene) was chilled to 0° C. under a N₂ atmosphere.Non-polydispersed mTEG (triethylene glycol, monomethyl ether, 7.8 g,47.5 mmol) was dissolved in 25 mL anhydrous ethyl acetate and added tothe chilled phosgene solution. The mixture was stirred for one hour at0° C., then allowed to warm to room temperature and stirred for anothertwo and one half hours. The remaining phosgene, ethyl acetate andtoluene were removed via vacuum distillation to leave thenon-polydispersed mTEG chloroformate 46 as a clear oily residue.

The non-polydispersed residue 46 was dissolved in 50 mL of drydichloromethane to which was added TEA (triethyleamine, 6.62 mL, 47.5mmol) and NHS (N-hydroxysuccinimide, 5.8 g, 50.4 mmol). The mixture wasstirred at room temperature under a dry atmosphere for twenty hoursduring which time a large amount of white precipitate appeared. Themixture was filtered to remove this precipitate and concentrated invacuo. The resultant oil 47 was taken up in dichloromethane and washedtwice with cold deionized water, twice with 1N HCl and once with brine.The organics were dried over MgSO₄, filtered and concentrated to providethe non-polydispersed title compound as a clear, light yellow oil. Ifnecessary, the NHS ester could be further purified by flashchromatography on silica gel using EtOAc as the elutant.

Example 39 Synthesis of Activated Palmitate-TEG Oligomers

The following description refers to the scheme illustrated in FIG. 9.Non-polydispersed palmitic anhydride (5 g; 10 mmol) was dissolved in dryTHF (20 mL) and stirred at room temperature. To the stirring solution, 3mol excess of pyridine was added followed by non-polydispersedtriethylene glycol (1.4 mL). The reaction mixture was stirred for 1 hour(progress of the reaction was monitored by TLC; ethylacetate-chloroform; 3:7). At the end of the reaction, THF was removedand the product was mixed with 10% H₂SO₄ acid and extracted ethylacetate (3×30 mL). The combined extract was washed sequentially withwater, brine, dried over MgSO₄, and evaporated to give non-polydispersedproduct 48. A solution of N,N′-disuccinimidyl carbonate (3 mmol) in DMF(˜10 mL) is added to a solution of the non-polydispersed product 48 (1mmol) in 10 mL of anydrous DMF while stirring. Sodium hydride (3 mmol)is added slowly to the reaction mixture. The reaction mixture is stirredfor several hours (e.g., 5 hours). Diethyl ether is added to precipitatethe activated oligomer. This process is repeated 3 times and the productis finally dried.

Example 40 Synthesis of Activated Hexaethylene Glycol MonomethylOligomers

The following description refers to the scheme illustrated in FIG. 10.Non-polydispersed activated hexaethylene glycol monomethyl ether wasprepared analogously to that of non-polydispersed triethylene glycol inExample 39 above. A 20% phosgene in toluene solution (35 mL, 6.66 g,67.4 mmol phosgene) was chilled under a N₂ atmosphere in an ice/saltwater bath. Non-polydispersed hexaethylene glycol 50 (1.85 mL, 2.0 g,6.74 mmol) was dissolved in 5 mL anhydrous EtOAc and added to thephosgene solution via syringe. The reaction mixture was kept stirring inthe ice bath for one hour, removed and stirred a further 2.5 hours atroom temperature. The phosgene, EtOAc, and toluene were removed byvacuum distillation, leaving non-polydispersed compound 51 as a clear,oily residue.

The non-polydispersed residue 51 was dissolved in 20 mL drydichloromethane and placed under a dry, inert atmosphere. Triethylamine(0.94 mL, 0.68 g, 6.7 mmol) and then NHS (N-hydroxy succinimide, 0.82 g,7.1 mmol) were added, and the reaction mixture was stirred at roomtemperature for 18 hours. The mixture was filtered through silica gel toremove the white precipitate and concentrated in vacuo. The residue wastaken up in dichloromethane and washed twice with cold water, twice with1 N HCl and once with brine. The organics were dried over Na₂SO₄,filtered and concentrated. Final purification was done via flashchromatography (silica gel, EtOAc) to obtain the UV activenon-polydispersed NHS ester 52.

Example 41

150 mg of salmon calcitonin (MW 3432, 0.043 mmol) was dissolved in 30 mlof anhydrous DMF. Then TEA (35 μL) and the activated oligomer of Example24 (42 mg, 0.067 mmol) in anhydrous THF (2 mL) was added. The reactionwas stirred for 1 hour, then quenched with 2 mL of 0.1% TFA in water.The reaction was followed by HPLC. Then the reaction mixture wasconcentrated and purified by prep. HPLC (RC Vydac C18 Protein andpeptide, 1×25 column, water/acetonitrile with 0.1% TFA, detection at 280nm). Two peaks, corresponding to mono- and di-conjugate were isolated.Samples were analyzed by MALDI-MS. MS for PEG7-octyl-sCT,mono-conjugate: 3897. MS for PEG7-octyl-sCT, di-conjugate: 4361.

Example 42

The procedure of Example 41 was used to conjugate salmon calcitonin withthe activated oligomer of Example 29. MS for PEG7-decyl-sCT,mono-conjugate: 3926. MS for PEG7-decyl-sCT, di-conjugate: 4420.

Example 43

The procedure of Example 41 was used to conjugate salmon calcitonin withthe activated oligomer of Example 31. MS for stearate-PEG6-sCT,mono-conjugate: 4006. MS for stearate-PEG6-sCT, di-conjugate: 4582.

Example 44

The procedure of Example 41 was used to conjugate salmon calcitonin withthe activated oligomer of Example 37. MS for stearate-PEG8-sCT,mono-conjugate: 4095.

Example 45

The procedure of Example 41 is used to conjugate salmon calcitonin withthe activated oligomer of Example 18.

Example 46

The procedure of Example 41 is used to conjugate salmon calcitonin withthe activated oligomer of Example 38.

Example 47

The procedure of Example 41 is used to conjugate salmon calcitonin withthe activated oligomer of Example 39.

Example 48

The procedure of Example 41 is used to conjugate salmon calcitonin withthe activated oligomer of Example 40.

Example 49 Determination of the Dispersity Coefficient for a Mixture ofSalmon Calcitonin-Oligomer Conjugates

The dispersity coefficient of a mixture of salmon calcitonin-oligomerconjugates is determined as follows. A mixture of salmoncalcitonin-oligomer conjugates is provided, for example as describedabove in Example 41. A first sample of the mixture is purified via HPLCto separate and isolate the various salmon calcitonin-oligomerconjugates in the sample. Assuming that each isolated fraction containsa purely monodispersed mixture of conjugates, “n” is equal to the numberof fractions collected. The mixture may include one or more of thefollowing conjugates, which are described by stating the conjugationposition followed by the degree of conjugation: Lys¹¹ monoconjugate;Lys¹⁸ monoconjugate; N-terminus monoconjugate; Lys^(11,18) diconjugate;Lys¹¹, N-terminus diconjugate; Lys¹⁸, N-terminus diconjugate; and/orLys^(11,18), N-terminus triconjugate. Each isolated fraction of themixture is analyzed via mass spectroscopy to determine the mass of thefraction, which allows each isolated fraction to be categorized as amono-, di-, or tri-conjugate and provides a value for the variable“M_(i)” for each conjugate in the sample.

A second sample of the mixture is analyzed via HPLC to provide an HPLCtrace. Assuming that the molar absorptivity does not change as a resultof the conjugation, the weight percent of a particular conjugate in themixture is provided by the area under the peak of the HPLC tracecorresponding to the particular conjugate as a percentage of the totalarea under all peaks of the HPLC trace. The sample is collected andlyophilized to dryness to determine the anhydrous gram weight of thesample. The gram weight of the sample is multiplied by the weightpercent of each component in the sample to determine the gram weight ofeach conjugate in the sample. The variable “N_(i)” is determined for aparticular conjugate (the i^(th) conjugate) by dividing the gram weightof the particular conjugate in the sample by the mass of the particularconjugate and multiplying the quotient by Avagadro's number(6.02205×10²³ moles⁻¹), M_(i), determined above, to give the number ofmolecules of the particular conjugate, N_(i), in the sample. Thedispersity coefficient is then calculated using n, M_(i) as determinedfor each conjugate, and N_(i) as determined for each conjugate.

Example 50 Cytosensor® Studies

T-47D cells (mammary ductal carcinoma cell line, obtained from AmericanType Culture Collection were suspended at a density of 1×10⁷ cells/mL inrunning buffer (low-buffered, serum-free, bicarbonate-free RPMI 1640medium from Molecular Devices of Sunnyvale, Calif. Approximately 100,000cells were then immobilized in an agarose cell entrapment medium in a 10μL droplet and sandwiched between two 3-μm polycarbonate membranes in acytosensor capsule cup. Cytosensor capsule cups placed in sensorchambers on the Cytosensor® Microphysiometer were then held in veryclose proximity to pH-sensitive detectors. Running buffer was thenpumped across the cells at a rate of 100 μL/min except during 30-secondintervals when the flow was stopped, and acidification of the runningbuffer in the sensor chamber was measured. Acidification rates weredetermined every 2 minutes. The temperature of the sensor chambers was37° C. Cells were allowed to equilibrate in the sensor chambers for 2–3hours prior to the start of the experiment during which time basalacidification rates were monitored. Cells were then exposed to testcompounds (Salmon Calcitonin or Octyl-Di-Calcitonin) diluted in runningbuffer at various nM concentration. Exposure of cells to test compoundsoccurred for the first 40 seconds of each 2 minute pump cycle in arepeating pattern for a total of 20 minutes. This allowed sufficientexposure of the cells to the test compounds to elicit areceptor-mediated response in cellular metabolism followed byapproximately 50 seconds of flow of the running buffer containing nocompounds. This procedure rinsed away test solutions (which had aslightly lower pH than running buffer alone) from the sensor chamberbefore measuring the acidification rate. Thus, the acidification rateswere solely a measure of cellular activity. A similar procedure was usedto obtain data for PEG7-octyl-sCT, monoconjugate (Octyl-Mono);PEG7-decyl-sCT, monoconjugate (Decyl-Mono); PEG7-decyl-sCT, diconjugate(Decyl-Di); stearate-PEG6-sCT, monoconjugate (PEG6 St. Mono); andstearate-PEG8-sCT, monoconjugate (PEG8 St. Mono). Data was analyzed forrelative activity of compounds by calculating the Area Under the Curve(AUC) for each cytosensor chamber acidification rate graph and plottedas a bar chart illustrated in FIG. 14 showing average AUC measurementstaken from multiple experiments performed under the same experimentalconditions.

Example 51 Enzymatic Stability

Compounds, supplied as lyophilized powders, are resuspended in 10 mMphosphate buffer pH 7.4 and then submitted for concentrationdetermination by HPLC. The phosphate buffer is used to create a solutionwith a pH that is optimum for activity of each particular gut enzyme.Aliquots of the compound thus prepared are transferred to 1.7 mLmicrocentrifuge tubes and shaken in a 37° C. water bath for 15 minutesto allow compounds to equilibrate to temperature. After 15 minutes, 2 μLof the appropriate concentrated gut enzyme is added to each tube toachieve the final concentration desired. Chymotrypsin and trypsin areresuspended in 1 mM HCl. Also, as a control, compounds are treated with2 μL of 1 mM HCl. Immediately following additions, 100 μL of sample isremoved from the control tube and quenched with either 25 μL ofchymotrypsin/trypsin quenching solution (1:11% TFA:Isopropanol). Thissample will serve as T=0 min. A sampling procedure is repeated atvarious time intervals depending on the gut enzyme used. Chymotrypsinhas 15, 30 and 60 minute samples. Trypsin has 30, 60, 120 and 180 minutesamples. Once all points have been acquired, a final sample is removedfrom the control tube to make sure that observed degradation is nottemperature or buffer related. The chymotrypsin and trypsin samples maybe collected directly into HPLC vials. RP-HPLC (acetonitrile gradient)is used to determine AUC for each sample and % degradation is calculatedbased from the T=0 min control. The results are provided below in Tables1 to 4.

TABLE 1 % Remaining Following 0.5 U/mL Chymotrypsin Digest ofPEG7-Octyl-Salmon Calcitonin, Diconjugate Time Non-Formulated BufferedFormulation 15 63 71 68 69 88 86 88 30 34 48 50 46 73 88 86 60 6 15 2015 61 69 84 Control Control 60 104 88 97 103 116 104 101

TABLE 2 % Remaining Following 0.5 U/mL Chymotrypsin Digest of SalmonCalcitonin (for comparison purposes; not part of the invention) TimeNon-Formulated Buffered Formulation 10 73 15 — 55 62 35 66 59 91 92 3030 26 40 13 42 54 86 87 60   1.6 5 12 1 12 55 82 85 Control Control 60 —100 93 45 100 102 98 103

TABLE 3 % Remaining following 1 U/mL Trypsin Digest of PEG7-Octyl-SalmonCalcitonin, Diconjugate Time Non-Formulated  30 87 89 83 90  60 78 86 7685 120 72 82 68 78 180 — 81 61 73 Control  60 103 100 120 106  105 99180 104 99

TABLE 4 % Remaining following 1 U/mL Trypsin Digest of Salmon Calcitonin(for comparison purposes; not part of the invention) Time Non-Formulated 30 80 50 82 87  60 66 28 69 76 120 44 7 46 59 180 — 2 31 46 Control  6041 101 120 69 16 102 180 7 101

Example 52 Activity and Inter-Subject Variability

Male CF-1 mice (Charles River, Raleigh, N.C.) weighing 20–25 g werehoused in the Nobex vivarium in a light- (L:D cycle of 12:12, lights onat 0600 h), temperature- (21–23° C.), and humidity-(40–60% relativehumidity) controlled room. Animals were permitted free access tolaboratory chow (PMI Nutrition) and tap water. Mice were allowed toacclimate to housing conditions for 48–72 hours prior to the day ofexperiment.

Prior to dosing, mice were fasted overnight and water was provided adlibitum. Mice were randomly distributed into groups of five animals pertime point and were administered a single oral dose of a PEG7-octyl-sCT,diconjugate (Octyl Di) according to the present invention or salmoncalcitonin (sCT or Calcitonin) for comparison purposes. Oral doses wereadministered using a gavaging needle (Popper #18, 5 cm from hub tobevel) at 10 mL/kg in the following 0.2 μg/mL phosphate-bufferedPEG7-octyl-sCT, diconjugate, formulation:

Ingredient Amount PEG7-octyl-sCT,  20 μg diconjugate Sodium-cholate  2.5g Sodium-deoxy-cholate  2.5 g Sodium phosphate buffer, q.s. to 100 mM,pH 7.4 100 gThe buffered formulation was prepared by adding 80 mL of phosphatebuffer in a clean tared glass beaker. The sodium cholate was slowlyadded to the phosphate buffer with stirring until dissolved. The deoxycholate was then added and stirring was continued until dissolved. ThePEG7-octyl-sCT, diconjugate, solution equivalent to 20 μg was added.Finally, the remaining phosphate buffer was added to achieve a finalweight of 100 g. Vehicle-control mice were used in all experiments.Dose-response curves were constructed using a single time point 60minutes after drug administration. These curves are illustrated in FIGS.15–18.

At appropriate time points, mice were ether-anesthetized, the vena cavaeexteriorized, and blood samples were obtained via a syringe fitted witha 25-gauge needle. Blood aliquots were allowed to clot at 22° C. for 1hour, and the sera removed and pipetted into a clean receptacle. Totalserum calcium was determined for each animal using a calibrated VitrosDT60 II analyzer.

Serum calcium data were plotted and pharmacokinetic parametersdetermined via curve-fitting techniques using SigmaPlot software(Version 4.1). Means and standard deviations (or standard errors) werecalculated and plotted to determine effect differences among dosinggroups. Average serum calcium data for various conjugates are providedin Table 5 below.

TABLE 5 % Baseline Calcium Drop at 2.0 μg/ Conjugate Dispersity kg dosePEG7-Octyl-sCT, diconjugate Monodispersed mixture 21.0Stearate-PEG6-sCT, diconjugate Monodispersed mixture 16.0PEG7-Decyl-sCT, monoconjugate Monodispersed mixture 11.5Stearate-PEG8-sCT, diconjugate Monodispersed mixture 11.0PEG7-Decyl-sCT, diconjugate Monodispersed mixture 8.3

Despite an in vitro activity as determined in Example 50 above that maynot be comparable with the in vitro activity of PEG7-octyl-sCT andPEG7-decyl-sCT mono- and di-conjugates, the stearate-PEG6-sCT,diconjugate, and stearate-PEG8-sCT, diconjugate, appear to have in vivoactivity (as evidenced by the drops in % baseline calcium from Table 5above) that are comparable with the in vivo activity observed for thePEG7-octyl-sCT and PEG7-decyl-sCT, mono- and di-conjugates. While notwanting to be bound by a particular theory, the improved in vivoactivity of the stearate containing conjugates may indicate that theseconjugates are undergoing hydrolysis in vivo to provide an active salmoncalcitonin or active salmon calcitonin-PEG conjugate.

In the specification, there has been disclosed typical preferredembodiments of the invention and, although specific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation, the scope of the invention being set forth inthe following claims.

1. A mixture of conjugates, wherein each conjugate consists of acalcitonin and a polyethylene glycol moiety, wherein the polyethyleneglycol moiety is coupled to an amine function of the calcitonin, whereinthe mixture is a monodispersed mixture, a substantially purelymonodispersed mixture or a purely monodispersed mixture.
 2. The mixtureaccording to claim 1, wherein the polyethylene glycol moiety has atleast 2 polyethylene glycol subunits.
 3. The mixture according to claim1, wherein the conjugates have the capability of lowering serum calciumlevels by at least 5 percent.
 4. The mixture according to claim 1,wherein the conjugates have an increased resistance to degradation bychymotrypsin or trypsin when compared to the resistance to degradationby chymotrypsin or trypsin of the calcitonin which is not coupled to thepolyethylene glycol moiety.
 5. The mixture according to claim 1, whereinthe conjugates have a bioefficacy that is greater than the bioefficacyof the calcitonin which is not coupled to the oligomer.
 6. The mixtureaccording to claim 1, wherein the calcitonin is covalently coupled tothe polyethylene glycol moiety by a hydrolyzable bond, anon-hydrolyzable bond or both.
 7. The mixture according to claim 1,wherein the calcitonin is covalently coupled to the polyethylene glycolmoiety.
 8. The mixture according to claim 1, wherein each thepolyethylene glycol moiety has the same molecular structure.
 9. Themixture according to claim 1, wherein the conjugates are eachamphihically balanced such that each conjugate is aqueously soluble topenetrate biological membranes.
 10. A composition comprising: themixture according to claim 1; and a pharmaceutically acceptable carrier.11. A method of treating a bone disorder in a subject in need of suchtreatment, said method comprising administering an effective amount of amixture of conjugates according to claim 1 to the subject to treat thebone disorder.
 12. The method according to claim 11, wherein the bonedisorder is osteoporosis Paget's disease, or hypercalcemia.
 13. Amonodispersed mixture of conjugates, wherein each conjugate consists ofa calcitonin coupled to at least one polyethylene glycol moietyconsisting of at least 4 polyethylene glycol subunits, wherein couplingbetween the calcitonin and the polyethylene glycol moiety-consists of anamine bond(s), said mixture having a molecular weight distribution witha standard deviation of less than about 22 Daltons.
 14. A mixture ofconjugates wherein each conjugate consists of a calcitonin coupled to atleast one polyethylene glycol moiety, wherein coupling between thecalcitonin and the polyethylene glycol moiety consists of an aminebond(s), wherein the mixture has a dispersity coefficient (DC) greaterthan 10,000 where${DC} = \frac{( {\sum\limits_{i = 1}^{n}{N_{i}M_{i}}} )^{2}}{{\sum\limits_{i = 1}^{n}{N_{i}M_{i}^{2}{\sum\limits_{i = 1}^{n}N_{i}}}} - ( {\sum\limits_{i = 1}^{n}{N_{i}M_{i}}} )^{2}}$wherein: n is the number of different molecules in the sample; N_(i) isthe number of i^(th) molecules in the sample; and M_(i) is the mass ofthe i^(th) molecule.
 15. The mixture of conjugates according to claim14, wherein the dispersity coefficient is greater than 100,000.